Hey there, I am in the process of pulling off my M4 full system and replacing it with a stock system (well, different cans). I bought some stock headers off of Ebay, seems like all the years match and nothing is bent or seems off to the naked eye. When trying to seat the 'main' part by pushing it up and onto the little rear cylinder pigtail header, it's really not wanting to line up with the two frame mounts on the bike. I can force it to line up with the right side mount but then the left side mount is still about 5-7mm off. Is there a trick to lining this up, like there's some orientation I should start from?