is there anyway to get better gears for the is350 like 4.10 or something... or can we only change it by getting different tire diameters..

if so.. i wonder what a 275/30 or a 265/30 would change the gearing 2..

i think first gear on an is350 is 3.52

 

Because I'm now an advocate for eliminating opinions from technical questions, I will leave the following technical answer:

Yes, changing tire sizes will change your overall gearing. Someone with Technical Info from Lexus could answer the question as to whether there are alternative gears that can be used (ie- if the ratos are different in the GS than the IS, but still use the same rear end)

But, your big problem will be that whether you change tire sizes or find new gears to put in, I don't know of anyway to re-calibrate the speedo. Plus, with all the electronics in the car, I'm wondering if changing the rear ratio will cause the car to engage traction control, or cause other "system" effects.

BTW, just so you know, my opinion wasn't a bad one, just a general statement, but you didn't ask, so I'm not stating

 

Didn't we do this in Jan. with the M5. http://https://www.clublexus.com/forums/showpost.php?p=3161025&postcount=57 We already have 4.08's

 

You need to consider the entire system. Transmission gears, final drive gears, and tire size. I have a spreadsheet I use for this. It looks like this:



Of course mine allows you to adjust tire sizes and final drive ratios. You can also (on another sheet) put in the torque and figure out the thrust at the tire/road interface which is what you really need to know anyway. And, this is the most important thing to understand when comparing cars with different drivetrains - the peak torque figure means almost nothing at all when comparing disparate platforms.

 

Recalibrating the speedometer is not difficult since the speedo is just counting electric pulses over time. There are several electronic devices that will adjust the pulses up or down by incremental percentages. I've considered installing one ($100) just for the purpose of fixing the stock speedo error.

I seriously doubt there would be any problems with VDIM since you would only be changing the drivetrain ratio.