not quite sure if this is the right section but here goes..

yesterday i was driving down to boston for HIN with about 9 other cars from my local car club when i noticed that if i floor the gas pedal, the car will buckle and stutter really bad. the guys that were with me figured its the spark plugs gone bad, so i went to advance auto and bought some bosch platinum +2 spark plugs (PN: 4312)...its what the guy at the counter gave me since i asked for NGK copper BPR7ES or BPR8ES and they didnt have either kind

my questions are:

1. will the plugs he gave me work fine with my car/mods (in sig)

2. are there better plugs i can get that will work better with my mods?

thanks in advance