Yea studs instead of bolts. The problem I had using my stock headers with my turbo setup was after welded everything back up, I could bolt 3 primaries up but the last one wouldnt line up, it was barely off. With the other primaries bolted on I could move the last one around but didnt have the strength or room to hold the primary in position while I tried to tighten the bolt. What I was going to do before I decided to cut it and do it again was use studs so I could get the front primaries on, then just push the last one back until it slide on the studs.