Rear lower control arms (LCAs) make the biggest difference in rear end handling.
The Maximum Motorsports or Steeda LCAs are the best.
If the rear is loose, LCAs will improve things a lot.
As for the front, steering rack Urethane bushings, caster camber plates, offset A Arm Bushings, Steeda XBall Joints. These will make the front more predictable and will improve geometry.
Since you have a convert, i think the first in the list should be a full length subframe to reduce frame flex, very very important on convertibles. A flexing frame is like having more moving parts in the suspension. The subframes will tighten the car and make the suspension work, not the frame.
Rob Hernandez, AFM co-Founder.