Definately take your time putting them on, if you can get a reliable and patient friend to help, at least to put the headers on (not needed for removing stock stuff) it can really help out. I had a real beach of a time getting my SLPs on by myself, most noteably cylinder #3, getting the bolt in was a real SOB. First time I did it I ruined the early part of the thread, so I was never really able to get the bolt in.

With some headers studs may be useable, dont know, with the SLPs the answer is no. Maybe on one or two threads (which alone would be a significant help). I would also recommend the FelPro exaust gaskets, because the ends are "slip fit" instead of having to thread a bolt through them (not that you couldn't mod another gasket like that). If you go SLPs another thing to watch out for, is the drivers side header, once in place and ready to be bolted down make sure that the bottom of the header is NOT hitting anything. This changes the angle of the header, and when doing the job by yourself its kind of hard to check up on yourself when your trying to hold the header, thread in bolts, while holding it dead steady with one hand and then stick your head "under the car," thats why I say get a friend for help during assembly if you can, someone under the car someone up top (tall person on top I spose).

MACs have thier own issues, but I'd go with them over an SLP for OBD I stuff, easier plug access, less problems burning wires.