Ah, i see. I doubt you will need to remove the turbo then, just the exhaust. I'd get the turbo to exhaust gasket and new studs and nuts. The studs may come out with the nuts but if they don't put one nut on upside down with the other on top and tighten them together to get them out if you don't have a stud extractor. Exhaust paste shouldn't really be used before a cat/lambda probe as it tends to clog them unless you have a decat pipe on? I personally haven't seen how tight it is on the gti to get to the turbo but I imagine should be room enough to do that.
