i just went thru hell with my starter a few weeks ago. First off. have a friend help you line up your starter so it bolts in straight. I kept getting this stupid little gap everytime i tried it myself.
Secondly, if you have an aftermarket starter your gonna end up grounding out, not be able to start your car and en up pulling your hair out trying to find out what the problem is.
http://www.zilvia.net/f/showthread.php?t=155857
that should help