I have it on mine, along with the brake upgrade kit. The back suspension isn't done yet. The handling is really good, but there are some quirks to it. Only put about 150 miles on the suspension though.
The adjustable shocks had a problem with the ring for the spring sleeve. They kept slipping down. I had to weld the ring into a solid ring on the shock. Why the shock body didn't have the ring molded into it, I will never know.
Customer service is top notch. I had a problem with the master cylinder from the brake kit, and he got it fixed quick.
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'84 3800SC, XP cam, 3.2 pully, HPTuners, N* TB, 4sp, SPEC 3+ clutch, Aluminium flywheel, pacesetter headers, F355 body kit, weight reduction