Running a 3550 but when I had it apart it had the TKO components inside. Had it apart for sychros one time. Just put stock stuff back in it. Since apart hurt 4th gear sychro trying to power shift and was not aggressive enough, this was leaving a stop sign on the street. So every shift into 4th is now notchy. I have a pro 5.0 shifter and struggle with power shifting. Partly as a clutch habit and partly due to the fact I don't want to tear it up.
I think the key is if your power shifting there can be no hesitation, you have to shift like your going to kill it.
I have heard many say they don't like high rpm's, I guess I have never really tested that fact.
I do struggle with the thing leaking, I don't know why but it seeps from the shifter, the rear seal even though that was replaced as well as the sleeve bearing and the speedo drive.
Scott