i hace tried the trd and b&m short shifters. i liek'em all. knock offs have been known to work just as well also. all worked fine for me, though some of the kncok offs arent made as well as others.
as far as installing a short shifter, it took me an hour the first time (+ goofing off) i can do it now in probably 15 minutes. check out this pdf file from b&m it should get u going and help out alot...
i know its for b&m, but installation is pritty much the same for trd and the b&m.
the shift knob (oem) is screwed on, if its glued just turn harder it should come off. (counter clock wise) if its aftermarket lower the shift boot at the base, there might be screws holding it in. get those off and u should be set