1. Exhaust mod you gain about 20 on the dyno and it does show on the drag strip. Caymandive can attest to that. Yes the exhaust mod is mainly a sound mod with some gains.
2. Intake is mainly a sound mod...check FIGS intake comparison thread and you will see what is the best. I would either keep it stock or get Joe Z or the ICode tube.
3. Headers, the best mod for power for our engines. Your looking at 30-40 hp gain. I would start with this mod if u want to make the car faster without changing the sound of stock.

 

why is an intake needed when doing headers and exhaust???

 

I've had the KN for more than a year (12k + miles) without any problems (still clean) and I did spin more readily after I installed it.

 

Just helps the car breathe in and out...

 

have you heard any of the other catback systems in person? (joe z, iss forged) if so, was the borla on par, louder, quieter than those systems? i actually have the borla catback arriving this monday and was worried it would be too quiet compared to the other two. (so, your comment has gotten me excited haha)

did you experience any drone?

 

With the Borla axle-back there is some drone but it's only under partial throttle at certain rpms (the magic 1800-2200rpm or so range). But it may not be drone...it's just a little loud/boomy. But by no means is it a monster. I had a cop behind me today and they paid me no mind.

Cayman one suggested that the midpipe design of the Borla cat-back actually helps with the drone. Based on what he described I think that's plausible.

I've heard the ISS, Joe Z, and Borla in person and I'd rank them in that order for sound volume, high to low.

And FWIW, at WOT I hear the (stock) intake growl more than I hear my exhaust.

 

ET,

How much of a noise increase is there with the Sikky Header?

 

Here

http://www.sikky.com/view_item.php?id=148&catid=15

 

My car was abnormally loud, I think I may have not tightened the bands enough or my gasket at the junction with the header may not have been flush. Plus I have the PPE headers.

Could not tell you about the drone cause I was too busy tailgating loud trucks to blend in during my commute. Was worried about getting pulled over. I have heard Joe Z and they sounds really nice.

 

I drove an IS-F yesterday with the Borla axle-back exhaust for the first time and I can confirm that it does have some drone to it. It's certainly not bad and can only be induced in certain situations such as at 60mph without downshifting under load, but I did find it a bit annoying as did the owner of the car. The thing with the axle-back exhaust is that the car doesn't really sound that much different than stock (at least from the inside with the windows up) so the slight drone is what you focus on since the rest of the exhaust isn't that loud.

Right after that test drive we went out in my car and he was pleasantly surprised how mine sounded. At the same speeds we tried to induce the drone and what we get is noticeably louder exhaust, but with a deeper burble to it without the annoying drone. So my original thought about the axle-back being more droney was right. A full exhaust certainly adds more decibels to the car, but it does cover up/balance out the drone that is noticeable when doing just the Borla axle-back.

 

very nice. thanks for answering my questions, fellas. my borla should be at my doorstep today/evening. installing this weds. can't wait!

 

Not to discourage but I would recommend against the K&N filter the way they trap dirt is using oil. This oil over time coats the sensors on the MAF which could lead to degradation and performance drop off. In other cars, it has even caused the sensor to die and malfunction. The aFe Pro Dry filters flow better and filter more particulates out in an couple different independent studies. Just my $0.02 feel free to look into this yourself.

To G9N
I've wondering about that - oil coating the sensor on MAF - myself (I just installed the K&N filter insert and collected about 1000 miles). My own experience with K&N filters in my RX300 has been mixed. I might switch to this: http://vipautosalon.com/store/index....-in-air-filter

 

caymandive = Every post is informative and useful as always. Thanks again.

FWIW I've decided to remove my Borla axle-back and go back to stock temporarily so that I can sell the Borla (I'm in the OC 92808 if you're interested). I'm digging the ISS DES cat-back look and sound but also considering the JoeZ since it's local.

Overall I thought the Borla axle-back definitely added some grunt but I haven't been generally pleased with the interior sound. It sounds awesome outside the car but I need to enjoy it inside too! It's just not wow-ing me, although it's probably personal preference.

The startup does sound mean as hell though.

 

If you guys really want power out of normally aspirated engine I would say

1. Headers - More flow = More power
2. Cam - bigger cam will change engine power
3. Pullys underdrive pully wind up faster get torque band faster
4. Intake you need more air into engine somehow
5. Exhaust more flow. more power
6. ECU tune to take advantage of all mods. Dyno tune is way to go for custom ecu mapping.

Just my two cents for a Lexus RX owner

 

Question for you guys with exhausts... where do you store your OEM exhausts if you don't have a garage?