I'm thinking of getting a link pipe for the r6 and chopping off the muffler box. Mainly for some better sound and the marginal power improvement. I'm just wondering if leaving the cat in the headers will have much affect on the volume and also the power.

Reason I ask is because I can get a full system with the link pipe already welded on, with the slipon included for a real cheap price, but the cat hasn't been drilled out.

If there is that much difference between cat and no cat, I'll just buy a link pipe and cut my own exhaust and drill out the cat.