Trading my E39 for a Z3, advice?

Any particular year Z3 you experts would advise I look for? From what I have read, this car should be a bit more reliable than my E39 540i (which really has not been terrible). Almost at 135k on my 540i and its running great so before it isnt (knock on wood) I figure why not trade it in for that convertible ive always wanted and try to score a better deal on one here in the cold seasons.

I would be looking at Z3's with about 60-90k miles.

Cooling repairs I am no stranger too, I had to replace the radiator twice on my 540 and the water pump once.

What I am worried about is suspension maintainence. On my 540i I had to replace lower control arm (*they are apparently normal wear and tear around 60-80k) and rear ball joints etc. Crap that was not that easy to fix (did it myself).

Any electrical issues? Other items that often need attention? Im not afraid to get my hands dirty to save some money. The Z3 easy to work on? I didnt have many problems working on my 540.

One thing to look to replace with the mileage you discuss is the shock mounts on the Z3. On my old Z3 (had just around 55K when I traded it last week) I had asked a couple of time for the service folks to take a look at the rear mounts in particular, and replace if looking at all worn or cracked. They kept telling me they were fine, and perhaps they were. Finally, this summer I simply told them to replace the rear mounts, which they did, and in turn advised me they were shot. Ride was noticeably different/better with the new rear mounts. If you do a search, you will see lots of threads address both the mounts and suspension. While I no longer have my '00 Z3, it was and is a great car, that provides an incredible amount of driving pleasure. Good luck with whatever you find, and enjoy the ride!

The 2001-2002 models are considered a little more reliable than prior years...

better water pump impellers
extra spot welds in trunk floor
Steptronic transmission if AT is what you're looking for

IIRC it was KBB or one of the other websites that claims these years are more reliable.