I have a 2016 IS350 Base model with about 20K miles. Recently had all 4 new Michelin PS 4S tires and alignment at the dealership. Disclosing it up front so that I dont get asked if its bad tires, bad alignment, etc etc. I also have IS-F LCA bushings (didnt go the FIGS route as I wanted a little smoother ride and less noise).

To be honest, I have hated the the drive for a "supposedly" sporty car ever since I got it over 2 yrs ago. Came from a bmw 3 series which would ride on rails at the corners without compromising on ride quality. My 3IS gets very twitchy in the corners and feels like I am about to lose my bowel. And under braking it felt like the car is deciding which way to turn. Thats when I replaced the LCA bushings as it kept the suspension swings under check. It did help for sure. And no inside tire wear to worry now. Please help me out here on how I can improve the drive.

I dont want to lower the car (may be a little if its required for better ride).
I dont want to go race spec suspension or anything. Something that keeps the stock ride qualify.
I mainly want to have a more stable car in the corners and under braking while retaining good quality ride and low noise.

What are my options
1. BC Racing BR coilovers?
2. BC Racing BR + Swift springs?
3. Stock shocks with RSR half-downs or swift springs?
4. Anything else?

If you have these setup, please impart some knowledge my way. Thanks.

PS: I have had MeisterR ZetaCrd coilovers in my NC Miata and loved them. But they don't make a kit for our car.


UPDATE: I have installed RSR Half-down with 15mm spacers all around now. Seems to have improved the handling a little better. Somehow the spacers did more than the springs themselves but I think it makes sense.

 

You could always try F-Sport struts from the dealer (maybe even in combination with RSR downs, this forum loves the downs and super downs). I'm coming from an e92 3 series that was on lowering springs and had the Msport package. The Lexus definitely took me awhile to get used to as it rides softer with a bit of rebound and body roll but it's still very confidence inspiring in corners once you get acquainted. Never experienced the twitchy-ness in corners however I did have an issue with heavy braking. I managed to mitigate it with better tires but I do plan on upgrading to RR racing's USRS LCA bushings. They have coilovers you could check as well. I personally will be ordering RSR's active best coilovers to keep the AVS function equipped with the F-Sport package. RSR does make less expensive coilovers without the AVS function where you can still adjust damping however none are cheap.

TL;DR- Consider RR racing coilovers and bushings, F-Sport struts, RSR coilovers or lowering springs.

 

Thanks for the reply @Lee350F . Since you mentioned about the FSport strut, how does it work without the AVS function on a base model? Are there manual rebound control available for these struts?

I do have the RC-F LCA bush on the car and I also ordered the Half Down springs from josh@meraki. Somehow I was not convinced about the BC racing+Swift with the ride height being too low. And RSR are way too pricey (may be rightfully so). I barely have 21K miles on my car and it still has a ton of life left on the stock struts. Half-down springs seemed like a good try at first. If I am not satisfied, I could sell them and then go with RSR later.

 

Check out posts on the front bushings. I had a similar problem with tire wear. Turns out the bushing is soft and it causes inner tire wear. I replaced mine with ones from the rcf and no longer have that issue.

 

 

As I said earlier, I already have the RCF bushes on my car.

 

Sorry for the late reply. To my understanding the RSR active basic models have a manual adjustment and the active best have a manual adjustment as well as an adjustment connected to the car's actuator (for lack of a better word) to adjust to different modes in the car. As far as the F-Sport struts from the dealer I'm not sure that they're adjustable. The part number I'm looking at is PTR1353094 for Front Left. I'd just call your local dealer with questions about fitment and functionality for the fsport shock as I'm not the most familiar with it.

 

I have the same feelings as you about this car's handling, especially the braking experience and the car becoming squirrely. At first I thought I just wasn't used to the car, but clearly a lot of other people noticed this issue. I haven't hopped on board the LCA bushings yet, but that's next.

What I found that worked for me was switching to lighter wheels and/or stiffer 280TW tires. I feel significantly less wander during turns and braking is improved. If I had to guess, I think it was the stiffer sidewall of the tires that made this experience possible. The ride has become stiff enough for all my passengers to notice, and I'm still on stock suspension. Some of my friends dislike the ride due to the stiffness, but for me, I enjoy it very much. Aside from increased stiffness, I'm also hesitant to switch to aftermarket coilovers because I already scrape my front lip as-is on stock suspension due to entries into and out of certain driveways beyond my control.

Last thought: I swapped back to my stock oem wheels with Continental DWS06 tires (for dealer visit) and the difference in overall ride is night and day to me. Preference given to the Yokohamas.

Just my 2 cents.

 

I have stock setup 225/255 with Michelin PS4S which are one of the very good tires. I blame it on the base model suspension on my 350. Anyways, I have RSR half-downs now with 15mm spacers all around. Seemed to have improved the handling.

 

I'm not sure what is happening here. The factory suspension setting on an IS platform is very stable. It is almost too stable that it is very hard to kick the back end out. and definitely not "Twitchy". You might be dealing with other issues like Stability Control/Traction or maybe bad shocks?.

With that said, any upgrade or performance mod would make the car more "twitchier". You can start by getting some good performance tires and try to make it as square as possible 245 front and 255 rear. Tune your rear camber settings with some camber arms to get rid of the god awful understeering. Then some coilver kits with soft spring rates so it won't beat you up daily driving. I wouldn't waste on springs unless you are upgrading the shocks. There isn't much you can do on an IS other than these mods.

 

I know you're responding to OP, but at least for me, the twitchy feeling is noticeable in 2 instances: 1) high speed braking and 2) certain turns. Mainly if and when I'm pushing the car at fast speed, and then I brake hard, the car feels as if it wants to deviate left and/or right. Also during certain turns, I turn the wheel giving initial input, but then I notice the car not exactly turning the way I want it to, so have to turn slightly more, and its just constant micro-corrections. This is very apparent on my stock wheels with Conti tires, but hardly an issue on my other set.

Ultimately, I'm chocking it up to the soft OEM LCA bushings that's causing me to experience all this. Plan and Hope is that Figs bushings will fix that.

 

I did noticed the braking twitchy and it seems that my USRS fixed the issue but I also upgraded the tires to Super Sport at same time. What you are describing in making correction might be an understeering. IS' have much more neg camber in the rear compared to the front which is made for safety precaution, not so great for turning.

 

2018 IS300 AWD F-Sport with stock rubber and 18" wheels. I also disliked the vague front end feel with a decent bump steer in an off-ramp I take every day. It starts with a slight downward angle then starts an uphill climb and starts tightening up with a pronounced expansion joint mid-corner. I'd say most sedans usually take this ramp about 30-35mph. I could push it to about 47-48 mph....no fear of the back kicking out, but the front feedback was not very inspiring, and sometimes I needed to lift the accelerator if I got in a little too hot with the front tires squealing too much for me. I was also getting some inner front tire wear. Replaced the stock LCAs with FIGS LCA bushing/brackets. With only that upgrade, I can easily push the car to 54mph (yesterday) while still accelerating...but usually have to lift the accelerator to merge into 45mph traffic. The front end has a lot more feedback and is more confidence-inspiring even in daily driving....no more excessive steering corrections at 70-90mph on the interstate either. I'd recommend the Figs upgrade to anyone. I'm sure the RR Racing LCA upgrade is comparable.

 

Do you feel that the rear is out of balance due to the stiffer bushings in the front? I just have the mindset that if I'm making a change to the front end of the car, a change should also be made to the rear. Stiff in front and soft in back is a concern I have.

 

Revised...I just noticed you track your car. The rear still feels solid. I do partly disagree with, "if you change something up front, you should change something in the rear." I would agree if your changing springs for example...you don't want to put RSR superdowns on the front and leave the OEM's in the rear. I used to track my motorcycles a little - with a bike I've had for a while, I could make multiple changes to get me close, then fine-tune from there. If I got a new bike, I changed one thing at a time so I could tell what worked and what didn't. On a daily driven car, you'd be hard-pressed to notice a difference in the rear with this mod....the track may be a different story if you are truly pushing the limit.