The biggest bang for the buck is big fat sticky tires. Get some 10 or 10.5 wheels and put some 295 or 315 all the way around if running A6s. The second most significant mod I did to my 99 was a watts link. Haven't run a panhard on it for comparison but I highly endorse the watts link. Just not sure if anyone makes one for the SN95 now. Mine was home made.
Of course the total package is always better.
99 Mustang GT - Auto-x/track car, 96 Townsend Chassis Late Model Stockcar (sold), 03 F150 - Daily Driver