I been running the Keisler 5-speed in my Challenger since 02. One tranny prob I ran into was the buzzing shifter but I have an old e-mail from them telling me to get it back to them and they will remedy the prob. I just can't get time to pull the tranny back out.
Other problem is a little more serious. the tranny fit ok but the set-up I have dropped the tail of the tranny slightly. I have no drive train issues, vibrations, or anything, but the oil pan on the engine is right up against the tie rod crossbar. I dropped the tie rod and dented the bottom of the oil pan with a hammer against a short piece of pipe, but is is still uncomfortably close. just my .02-