My thoughts on Nitto Invos...
 

Ok, so I recently got a set of Invos on my 09 sport coupe, and I've noticed at high speed cornering around curves that the car now feels "squishy" and I definitely lack confidence in the turns now.....car almost feels like it wants to "step-out" at first and then it grips like hell and I can even accelerate through turns. Any ideas or tips that can help this? I have a set of tein springs and 20mm spacers ready to install if that helps????

Sounds like squishy sidewalls and squirmy treads. Try more pressure.

I've had that on my mind, right now I'm at 32 all around. I'm gonna try 38 rear and 36 front I think

I had a set of Invos in sizes 245/35R20 and 275/30R20. I really liked how they felt. There's an on ramp that leads to the freeway going home and I can corner through there pretty quick on those tires. I've kept my pressures around 38psi.

Did you stick w/ stock tire sizes? If you went quite a bit wider than stock that will affect sidewall stability too.

Don't get too radical with your change. I would try 36 F/R and see how that feels. Generally, the rear should be a little softer than the front to make sure the tread stays flat to provide the most traction since it both deals with lateral G and engine power.

38 all around. Remember front carries more weight

Gradually change air pressure to see what fits. You don’t want to over inflate. Remember the hotter the day the higher the air pressure will be.

Remember the recommended pressure is cold pressure