Get a Twin Turbo. There isn't a whole lot of maintenance difference between the two.. other than the obvious, turbo/intercooler and the bunch. But as far as "care" for the turbo system..... oil changes, letting the car idle for a couple of minutes after running it, and letting it warm up as well.... I don't see how the care is so hard? I am the owner of a 1990 Twin Turbo and lemme just say, I LOVE IT! If you really want to learn A LOT about the Nissan 300zx (1990-1996) check out:
http://www.twinturbo.net and read through the FAQ and use SEARCH to look for answers to any questions you may have... I think you'd be very happy with a Twin Turbo in the end.