Well that's very, very, good of them to offer you your money back that you paid them for work not completed :jaw drop: If it were me in this situation I don't think I've have settled for that!! At the very least I would have expected them to have arranged to have the seats sent back to carry out...
I gutted the cat and installed mivv slipon with no problems at all (except the popping on decel with the baffle out, baffle in a lot better) power commander will be needed when you take the mods beyond that
obviously very neglected in that area and probably due to lazyness not wanting to remove the lower fairings, you'd be surprised how that lot would clean up with a few hours of your time, some de-greaser and a can of acf-50, those headers won't need changing, I would however insist the dealer...
I've recently gutted cat and installed mivv can with no probs, got Ivans flies, FCE and AIS block off plates all ready to go but won't be installing any of them untill I get my PClll