The crap on the interior plastic notwithstanding, I would go for the 240z! RWD, old enough to be smog exempt pretty much anywhere, lots of aftermarket resto parts, lots of interchangeability with almost every RWD Nissan car built from 1968-1988, and the possibility of an engine swap(RB's are do-able

) makes it an easy choice. There are even kits out there to put a Small Block Chevy V8 in it and have nice, cheap horsepower and good handling.The 200sx is much harder to build as it is FWD and has a more limited selection for engine swaps.The GA16DE can be built, but it would cost as much as the 240z to do a turbo kit properly (I.E. Hotshot) and then you still have a weak trans to contend with. Go for the 240. You'll be much happier.
__________________
1998 Nissan Frontier XE/2wd/5spd 1 owner, 264k miles
1985 Olds Cutlass, 350 Chevy, owned for 14 years
WANTED: 1968-1973 Datsun 510 or 1991-1994 Sentra SE-R
http://www.myspace.com/junkyardengineer