revisiting suspension/tires - need input

[Shadow24V]

ok, ive had my car up and running for a while until i killed the motor at the track. one thing i did notice was how much squat i was getting off the line with the stock rear springs and original 92 shocks. these will be replaced this summer and my coilover suspension finished. i dont have a clue what the spring rates are on my coilover kit ($20 ebay/china kit) but so far its been good on the front. A little stiff (small bumps skip cds, but i also have a cheapo walmart stereo). ok onto what i need some advice on:

in addition to the rear coilovers, i would like to add a sway bar to help handling. Ive also read that if i lower my p-body, i have to adjust the panard bar which makes me think i should just make an andjustable one and replace the U-channel original one. would changing to a stiffer panard bar help in any way? im looking for overall balance, not a straight drag car

the other question is rims/tires. my 195/60R15 cooper all seasons dont have much grip, especially off the line. i can only launch at 1500-1800 rpms as anything more results in excessive wheelspin. I was hoping to find some SRT-4 rims (17x7) and get some good performance tires for them. Would the larger rim size have an affect on the car? (rotational inertia etc) and what would some other recommendations be if i cant get SRT-4 rims? (rim size, width etc)

thanks in advance.

[Sittn86]

Put airbags in the back & pump them up at the track. Get some slicks.