I'm chuffed to bits with my Z3. It was a low owner 46k miler with loads of history, 2002 and only £4.4k. Lots of smiles for the money. I use it a lot more than the kit and it's been a nice change.......BUT I really do miss the rawness and sheer noisy grunt of the Hood, as well as the head turning nature of it.
I looked at Z4s and thought they were very bland...at least the Z3 is a bit more retro looking. Supposedly they don't drive or handle well but I disagree.
I nearly bought your V8 from Alan before you did and it's a terrific motor....be careful what you wish for as anything mainstream, even at your budget, could well be a serious anti climax.
Good luck, be interested to see what you end up with.