On the P5, the dustcover can easily be removed and replaced: there are a couple of vinyl tabs at the back of the cover that fit into brackets at the rear of the plinth. The P7 should be exactly the same. However, I don't think there's an easy way to remove the plinth -- it looks like it's glued on rather than attached with screws.
Regarding the Exact cart, I find it very satisfactory with my P5 and have little desire to experiment -- an added advantage is the absence of alignment issues when you use it with a Rega arm.
Regarding the Exact cart, I find it very satisfactory with my P5 and have little desire to experiment -- an added advantage is the absence of alignment issues when you use it with a Rega arm.