The truck is an 18 f150 diesel. Running bilstein 6112s and a 1" spacer since the 6112 coils are for gas engined trucks, I lost .5" of lift. Jbas upper control arms have enough geometry to unwind the spring. The stock control arm was sucking the spring up. They are built extremely well and I am very impressed. I actually came put with 1" of lift over the stock arms. It can only be that the stock arms was preloading the strut. The cost is tough to swallow. I think $600 is on the high end. I'd feel more comfortable at $400 price point. But have no regrets.