Front sway bar
#2
I took mine off my truck and made very little differance for normal driving. Now slamming lane to lane you can tell a differance but still isn't really obvious. I don't know that I will put it back on since I originaly took it off for going to the track tomorrow. I would assume your car will be similar to my truck and you won't hardly know it is gone.
#3
if you have good shocks up front, and your rear suspension has poly bushings then you wont notice it much unless you are trying to carve corners. but thats a no brainer. i would also recomend tightening your rear swway bar endlinks to get rid of as much play as posible. good luck