...... bloody AP CP2000-8 is slipping if I go over about 17-18psi!

Looks like my new wheels are going on hold and it's time to splash on
another new clutch!
On a positive note I must be making fairly good power for it to slip as the boost comes in nice and smooth without much of a torque spike (boost was hitting about 21psi and holding around 18-19psi, just before slipping)
Are there any alternatives to the AP CP2000-35?
As that is the best they do before going paddle which I dont want to do!
Karlos.
PS... it is fucking lively though!!