[RickyBobby]

I was in your situation after dealing with knockback for nearly 20 years on various cars with stoptech's. I have always installed springs in all of my Stoptech calipers and while it helps, it doesn't eliminate the knockback completely. I finally bit the bullet and got the AP's and the knockback was completely eliminated. I couldn't believe the drastic difference I felt.
I agree with you that the stoptech's served me well over the years. Pads, rotors, rebuild kits are plentiful, but the same looks to be true for the AP's.