Friend has a 2005 GSX 600 H.O wants to clutch it whats a good clutch setup does alot of trails

Cudney clutch kit...made in Canada and one of the best guys to deal with in the business.

http://www.cudneyracing.com/skidooproducts.htm

Lots of options out ther ebut 2 of the best have to be Cudney and Dynamo Joe. Both sell kits to really wake that sled up.
Since cudney is already listed here's Joey's site

Increase your clutching IQ by clicking here (http://www.mxzx-revzone.com/)

ditto........

I installed Dynamo Joes kit on my 05 MXZ 600X. It did everything he claimed,I was totally satisfied,drop in kit,no playing around to get it right. A WINNER!!!!