Those of us with verts have had limited options when wanting to lower our cars. The R52 is lighter in the front but heavier in the back than our R53 cousins. Most manufactures say their lowering springs work across the board, 50/52/53 but they really don't so for years coilovers were the only real option if you did not want the rear end to ride on bump stops. I bought a used set of Koni Coilovers really cheap. They are the older version without any helper spring. Basically a Koni Yellow with an adjustable perch that came with Eibachs. I also know a little about figuring spring rates based on the wire thickness and the number of coils (gets tricky when the some coils touch once loaded aka progressive rate) and could tell the rears were not going to work. I put them on anyways to see what the drop would be and it turned out whereas Koni said basically one inch for the R53, they dropped the vert two inches. Ended up riding on the bumpstop. I even took a pair of used R52 OEMs and cut them, something that is pretty easy to do as the OEMs are linear rates. The problem there was the R52 OEMs on a JCW are pretty stiff to start and when you cut them they get up over 400 lbs so instead of lowering, they actually raise the car up. I kept doing research and came across AST that has a specific kit for the R52. I was hesitant at first but had a very good conversation with Sean Myers the NA Rep. He even noted that they block test their products and guarantee the lowering values to within 1 to 2 mm. The kit says the back will drop about 3/4" whereas the front will drop about 1 1/4". Quite happy with the results but with the top down the rear will drop down to 1". The ASTs would be a good option with some Koni Yellows.
Good post - didn’t think about the difference in weight. The wife is wanted a vert.. been looking at them. I’ll have to consider this as it won’t stay stock. That said, have Koni Yellow top adjust on my 88M5 for 8 years with ground control coil overs. Been great.. no issues. How does it handle with the top down?