Has anyone fitted a final TRD gear ratio on a Lexus IS200?

You can get any diff ratio you want just about, from other Toyotas...

Any 80s or 90s Toyota with an F series diff has got a crownwheel and pinion that you can use in an Altezza diff.

I think some of the vans came with a 4.5 or a 4.7, which I think is the ratio of the TRD final drive.

Not really an improvement though IMO unless you've got a motor that revs a lot higher...

Seeing as how the TRD final drive is most likely to suit the 8800rpm 3SGE, it's probably not so good for a somewhat less revvy IS200.

If assuming as per your sig that your car is supercharged, then you'd most likely want something like a 3.7 or 3.9 ratio final drive instead.

Easy to find crownwheel and pinion in that ratio!

Thanks for the given information :)

I have the TRD one in mine 4.56 or something, keep in mind i race mine, but at eastern creek i am only just geeting close to the rev limit in 5th gear I think I worked it out to be just over 200kph but never use 6th... I am thinking of going to a 4.9 or a 5.3 just awaiting prices on the CR & pinion now

You're probably better off keeping it how it is...

Generally people set the gearing to use 1:1 gear (fifth in this case) at top speed required?

there's a pretty big drop from 5th to 6th, it's just there for cruising at low rpms on the street car really.