I think your fine. When I installed mine for the first time, the donuts do not sit well for me, as the flanges were a little "off" once again...dropping big bucks for a part, that doesn't have very good fit for the amount spent on it. Highway robbery I tell you! LOL After they have been on and off a few times...maybe 2-3 times total so far, they gaskets actually fit better IMO. Like the pipes will bend, and mold to the correct shape after use.
Their instructions suck for sure, as many do for after market parts, but its not rocket science to install them. I looked through them briefly, but didn't really go off them when I did the work.
With them being run for a while, I have never had to retighten my bolts. Either on the header to the head, or the cross over. I used new GM exhaust gaskets on my heads with no type of sealer on them as well, installed dry. I have never been a fan of Fel-Pro gaskets, and having to redo a job well done because of gasket failure on their part.
Never hurts to check the bolts later down the road. But if they are tight, and installed good, I don't foresee you having any problems down the road.
~F~
