When my stock clutch started slipping on my 99 Drifter at 17,500 miles I went to my dealer and he explained that was within normal Kawasaki wear parameters. His quote on a new Kawasaki clutch was obscene so I looked aftermarket for a replacement. I spoke to someone at Sherms and he told me about the Gorilla clutch.
He said the stock clutch pack on their Kawasaki was good for only a few passes on the drag strip, but the Gorilla clutch has over two hundred runs on it and was still going strong. He convinced me and I opted for the optional stiffer main spring that Gorilla also offers, the downside of which can be some wheel-hop when downshifting into 1st gear while traveling too fast.
I had no trouble installing this new clutch following the provided instructions, it took me an afternoon to get it done. I`m very pleased with the performance of this replacement clutch and spring.
http://www.mobbley.com/page/61866202 (http://www.mobbley.com/page/61866202)
When I upgraded my stock spring plate and holders, I installed their friction plates. No trouble with them over the past 10K or so.