I recently switched my stock Bridgestone potenzas for Michelin Pilot Sport PS2's. I took the car to Butler Tire and I had them fill the tires with nitrogen. Overall, the difference is HUGE. I love how the car feels now. It is like a whole diffferent animal in turns and it grips and rides so much better. I can't even begin to say how much I love these tires. I would highly recommend tryiing them out when you need new tires.

What you're noticing is the difference between a high quality tire and the
POS tires your car came with. Nitrogen will keep your tires inflated at the
correct psi longer than air but that has zero to do with the ride you're
experiencing.......enjoy!

I just got some ps2 with my sf's today also, came from falken 452, i can can say they are alot smooter, def worth the money

I'm also finding that my PS2's are lasting a LOT longer than my previous toyo's did. I've had them on for about 16k miles and tread still looks deep. I don't take turns to hard but I do like to accelerate and drop to third or fourth gear when the freeway is clear.