if mine is still available after tomorrow you welcome to stop and look at it.
http://www.zpost.com/forums/showthread.php?t=1211344
Otherwise, if they are not beat, that's not a bad price. If not already done +1 on FCABs, RTABs, shock/strut with all mounting components, sway bar links. Really depends on whether it was run hard through the twisties all the time or not. Most likely not if it the cars are in Miami. And this stuff doesn't necessarily need to be done right away -probably within 20-30k. If autoboxes you might want to think about tranny fluid; water pump/thermostat too.
SI's all came with staggered wheels, sport suspension, slightly larger brakes and sport button. This is the Z4 sport package. M-sport seats were an option. M sport steering wheels were not an option but lots of us have put them on. I adapted mine for the paddle shifters and loved it.
These are very toss-able, fun cars, that if maintained, will probably do 200k without a problem. Only issue I had was suspension related. When I first bought it at 30k miles, as a CPO, it was twitchy at speed. Had it aligned by a reputable shop(not BMW); turned out front and rear toe in were almost non-existent.
Bottom line: Alignment and suspension need to be maintained correctly and rubber wear parts(FCABs/RTABs) need to be replaced at 60-80k. If not, its not fun, doesn't track so well, and don't blink at speed.
Even when this car is correctly set up and maintained there is just a little too much assist/too tight a ratio in the steering. It will go, where you point it; predictably, but quickly. Many autocrossers love this as its great in the twisties.
Good luck and hope you find a gem like mine.
Bruce