Unreliable? Hell no. Get a Z that wasnt abused and tokeep it happy just do oilchanges every 2-3k miles.

Hell, my Z has blown turbos (Not from wear and tear, but from a previous owner driving it into water and fuckin them up) and my car runs damn fine. Doesn't smoke, etc. etc.

And you can get 500hp easily on a Z for under 4k.