A boost leak and a slipping clutch will have very different symptoms. When the clutch slips, your RPM's will rise quickly but the car will not accelerate. When you have a boost leak or tuning issue, you will have an overall lack of acceleration, but RPM's will not rise either.

The Exedy is definitely the cheapest option out there and will hold the power just fine. But as some have said, they do tend to have less smooth engagement than other more expensive clutches.

Thanks
-- Ed