I was wondering why no one had suggested this previously. I can make the car understeer and oversteer in the same corner, all based on driver input. The hardware can certainly help but the fast way is to definitely change the driving style to eliminate the understeer. That generally means all braking in a straight line *before* the turn and application of power appropriately to not push. Being at the edge of traction means that you can be in 2nd gear in many cases and use throttle to position the rear.

Driver style should always be the first thing to change - can save lots o' $$$

 

Wing, it may be difficult to give recommendations for you because of your aftermarket springs. I personally don't know what those springs have done to your handling balance. Maybe the springs accounted for your understeer, or maybe it was some combination of the tires being 3 years old, having the extra-narrow stock front tire, your alignment, and your driving.

I can tell you for sure that with stock springs, you'll want a stiffer front swaybar if you run V710 tires.

 

Regarding my tire pressures with the RS-2s, I ran 36psi on all four corners. I didn't really get crazy with pressure experimentation as I was just focusing on driving. I find it very refreshing to run on street tires every once in a while. It's just fun sliding around a bit more.

Oh, the Hankooks will be really kinda crappy feeling until the tread blocks wear down a bit... and then they drop off when you get down to the wear bars. But... they're cheap!