You need to confirm it's a D model not a C. Either one you can get pretty cheap even in good working shape, less than $2,000 for a C probably. The D model was made from 1990 to 1993 and was replaced by The E model but sold along side the E in '93. The E was sold from 1993 to 2004 I think or 2003. The D and E have the same engine, the tranny was improved for the E, the D is the oringinal ZX-6. The E has a better frame, all aluminum and ram air. The D model, which it sounds like it is, uses probaly all the same engine parts as the 1990-2004 ZX-6D or E, the the forks and rear shock can be swapped, pipes can't, airbox can't, seat can't, tanks are different too and fairings. Unless its engine related or suspension you'll likely need to stick with '90-'93 zx6D parts.