04 Gs-430 16" Vs. 17" Tires

[1693power]

I drive an '04 GS-430 that I bought used. It came with a very noisy set of Diamondback 235/45 17 tires on it. Well, 35k mi later, they are done. I am shopping for tires, and notice that the 17" lo pros are more expensive than the higher profile 16" tires that would come on, say a GS-300 or GS-400. I also assume that most of the lo pro 17s will be noisier than good old 16s, and that the 17" lo pros will not last as long. I put 256k miles on my old '98 LS-400 with 16" rims, and I regularly saw more than 50k mi out of a set of tires.

So, I am considering getting rid of my OEM 17" wheels, and putting an old set of 16" OEM rims on the car off of Craigslist. Assuming I use the OEM 16" tire size, are these wheels and tires the same exact rolling diameter as the OEM 17s? Or put another way, other than the wheels and tires, are GS cars with 17" and 16" tires identical? Or is the final drive ratio different, or speedo settings different? I don't want to make the change if it changes a bunch of other things, too.

I drive 35k mi/yr on SoCal freeways, 80mph at a time. The car is bone stock, I'm not looking to lower it, etc. I just though maybe the 16" rims and tires would be better suited for me, as I think they will last longer, be quieter, and cheaper to replace.

Thoughts?

[1990LS400]

No problem at all. Check the 04 GS specs for the tire sizes to use with the standard 16" and optional 17" wheels: http://www.lexus.com/contact/pdf/2004/2004GSspecs.pdf

[SKperformance]

size is not the issue cheap tires are the noise problem.

[kevinjones]

A 300-horsepower engine delivers enough might to make your head spin, while the luxurious cabin is seductive enough to turn heads.Its front seats are heated and ergonomically designed for comfort, yet upholstered in perforated leather much like cars built for the track. The sound system alone comes with an in-dash, six-disc CD auto-changer and an available Mark Levinson® Premium Audio System.