I have a set of Koni Yellows for a non-M Z3. I had them on my car (318ti) for 5,000 miles. Bought them used and was told they had been on a Z3 3.0 Coupe for 10,000 miles.
I ran these with H&R sport springs in the front and TC Kline 400 lb springs in the rear. Was a very nice setup, the linear rear spring made handling much more predictable.
None of them leak, all compress and rebound nicely. All of the adjusters work. I also have the adjuster tool which is included but not pictured.
According to Koni's website these will fit all non-M 4/6 cylinder Z3s from 96-2002. They also work on the ti just fine.
SOLD Looking to get $275 + shipping obo for the konis.
SOLD Front H&R sport springs for 318 models. $100 + shipping.
SOLD TC Kline 400lb rear non-shorty springs. $100 + shipping.
SOLD SOLD TC Kline 500lb 60mm shorty front coilover springs $70 + shipping.