just wanted to give my experience with and aftermarket downpipes for my lb7 , so I read on other threads and other forums how big of a pain in the arse it is I thought I would give it a shot so I soaked the bolts and nut with PB blaster for a couple days just occasionally walk out and spray the bolts even drove back and forth to work after spraying and I think the key that made it so easy was buying a flex head ratchet the bolts and nuts came right off with a little muscle and then the hard part was getting the downpipes out which was a pain but all in all took me 3 hrs to do the whole job.