Hey,
I've been digging around with no luck, the local Mini parts guy seems to think the JCW stage 1 and the Sport & MCS tips are all interchangeable.. but he's not sure. They can be ordered separately (about $80ea).
contemplating deleting the 2nd cat & adding the tips for a 'cheap' oem-quality exhaust upgrade.

 

I imagine that they could be. I know the Factory JCW exhaust has them welded on, but the piping that comes out of the muffler itself is actually larger too.

The JCW tuning kit exhaust seems to be the same size exits out of the muffler (maybe just more straight thru like the Factory model). I know people are taking the MCS Sport tips and just using the set screw for their 1st gen MINIs exhaust, so I imagine it would be cake.

 

On an R56 the tips are not interchangeable. The JCW etched tips will not fit on an MCS exhaust