I've read most of the postings related to suspension upgrades, but most of you appear to own GS4s, so I'm not sure if it's really an apples-to-apples comparison. My 300 came with 16" Bridgestone Turanza 215/60s that really suck. I replaced a BMW 528i with sport suspension, so I know great handling. What's the best order of upgrades to improve the handling on my GS and not seriously deterioate the ride?

I figure going to 16" performance tires would help, but enough ? I'm willing to upgrade to 17" wheels & tires and/or do the L-tuned suspension upgrades. For those of you have been down that road (especially with a 300), where will I get the most bang for the buck?

Also, exactly what effect does the steering ECU change have?

 

Welcome.

First I suggest how firm of a ride do you want? If you don't want to void your car warranty, I'd opt for the L-tuned suspension. There are few members here with that setup and is satisfied with the handling. It lowers 1.2f and a little under an inch in the rear.


Second, if warranty isn't a factor, and want an even firmer and lowered look, I'd opt for the H&R/Bilstein shock combo. It lowers 1.4f and 1.3r. The handling is phenomenal and you can get Bilstein from Gs4will on this board. Its the cheapest price that you will find anywhere ! Also comes with a lifetime warranty.


The second one I mentioned isn't too harsh of a ride that you won't get from a Bmw.

One last thing, if you opt for upgrading your wheels, try to get atleast 18's aftermarket. Most people when they upgrade in wheel sizes, get atleast 18 or higher.

 

Steering ECU will tighten the steering, obviously. If you want performance, 18x8.5 front and 18x9.5 rear would be the best combo IMO. Anything more than 18inch is for the look. For lowering, if you are concerned about the ride, TEIN CS and APEXi WorldSport coilovers.