whats next?
 

I have a 2011 gt, brembo package, suspension mods so far are: eibach pro kit springs, koni yellows, steeda adjustable sways, max motorsports camber plates, adjustable panhard rod. I'm looking for better handling for autocross, track days, mountain driving, and in the future some scca hillcimb races. What suspension mod do you guys recommend next?

Better tires and wheels wide enough to properly support them. You're already way past F-Street autocrossing, so you need to be looking at wheels that are at least 10" wide (preferably wider).

Start driving it at one or more of those activities, plan on gradually finding out what still needs to be improved and fixing those things as you go. Just for starters, initial settings for those adjustable bars are unlikely to be optimum or final, and you should expect to tinker with camber. Then there's rear geometry tweaks and careful reductions in suspension compliance in general.

You may find that "better handling" is actually a moving target.



Norm

I should have mentioned I am planning on getting 18x10,s before anything else , but im not sure on tire size, I want 275's on all 4 but if I go with a 275/40/18 it will look good and lower the car a bit, but I'm concerned about the gear ratio effectively changing, I already have 3.73's and not wanting to increase the rpm's at the autocross or highway, but if I go with a taller tire, I lose the lowering effect and it might look like a truck tire, and advice?

The effective gear ratio isn't going to change all that much - even if the 275/40 is a full half inch shorter than your OE tires, that corresponds to less than a 1 mph change for every 50 mph. You might run into this a little more frequently at autocross than with the OE tires (where you won't want to have to grab 3rd) but it isn't likely to bother you at all on the highway. If you even notice the less-than-50-rpm difference there.


Norm

If my calculations are correct, going from a 255/40/19 to a 275/40/18 would decrease my overall tire height by 3/8 inch, doesn't sound that bad I may give it a shot