clutch life-span?
To save you some more cash and not have to go with a higher end clutch but still a step up from stock. I can highly recommend a Clutchnet.com clutch.
Just yesterday I dropped my clutch and it has exactly 70k from when I first put it in bout 5 years ago, and I was really surprised to see it held up great, and still had roughly another 10k on it. I remember I paid really cheap for it alone back then, and boy did I hammer that thing. It's american made. Their pricing and website has changed some since back then but from what I saw on the faceplates yesterday it was a good value.
Oh yea sometimes a vibration is a driveshaft that needs balancing. Make sure u try that b4 diving into a rear.

