one thing you want to keep in mind is if your going to drag the car the 5 leafs would be better as there rated for race set-up. i was going to go with the even stiffer ones but have a set of single and will use a stiffer shock instead. also for your sub frame, i beleive you can contact bill edmunds(firebirdbill). he should still have the convertible in the barn. subframe is straight but needing minor repairs in the mounting area. subframe mount in rear are rusted a bit. been siting for 15+ years in same spot!! i vouch for him also!! and hes in the tri-state area. columbus, oh to be exact. you could even pick it up.