If you're going down the welding route then you'll need to cut the join and weld a sleeve in place, or we can help with a new replacement exhaust system...
We've just done a set of Grids in 19" for a GT4 owner, if it's 5 spoke you're after then the 19" GTR wheels we do have a few colour options available...
Simon, ironically the same setup as yours including the exhaust system went through the emissions with no issues at all, he's also got the UpRev too...
Dan, common fail area is between the mid and rear join, what sort of budget do you have in mind, as the Cobra resonated we do at £425 makes an excellent replacement...