"I bought my '94 used in 2003 with 140,000 miles. It just turned 222,000 and is still running strong and passes CA smog with no problems. The only unusual problem I've had is with the engine mounts breaking 3 times which in turn has broken two exhaust manifolds. I gave up on that problem and have been driving it the last 20,000 miles with an exhast leak and a broken motor mount.
(PS I have owned two 300ZX's with the same engine and drove both to over 300,000 miles.)"