Dude, come on, Don't count out fwd 4-bangers yet. For the kind of performance 99% of people in this world need, it will be fine.
300zx just plain aren't that good of cars. I think they are totally cool, but they just aren't worth it, and their performance honestly is nothing to write home about. First off, the N/A 300zx is just pointless and stupid. Second, any turbo 300zx is gonna probably have high miles and if it hasn't already will need the turbos replaced= $$$. Plus, they are heavy as shit. Hell if you are gonna get a rwd Nissan get a 240sx. Cheap, tons of parts and upgrades for them (can you say sr20det?) And most importantly, they have almost perfect 50/50 weight distribution.
Older Bimmer= crap shit performance. I've driven older bimmers, they fucking suck stock. BMW is probably my favorite manufacture of car, but the older ones pre like '95 I feel have shitty build quality and their perfomance blows balls. Honestly. Unless you drop mad dough into it. And if something happens, which you always have to account for, you are fucked. Do you have any idea on how much it costs to rebuild a Bimmer motor, let alone an M series motor. It is mad expensive, whereas you blow a motor in a Toyota or Honda and anybody can fix it, and for pretty cheap.
I just don't see your justification, but hey, cars are personal choices so do what you want. Just don't be pissed when you have problems with your 300zx or Bimmer and you can't afford to fix it.