A lot of guys prefer the pro 5.0 shifter, but use the Tri-ax handle. I personally prefer the Pro 5.0 handle myself. They are both made really well. The tri-ax has a handle similar curve to the stock one; the throw still feels a little long to me, while the pro 5.0 is a strait up handle, and for me its easier to throw. Short arms= Tri-ax. Long arms= Pro 5.0.
from all the threads ive read about this, basically whoever has a tri-ax will say the tri-ax is amazing, and whoever has the pro 5.0 will say that it is amazing. the only consensus is that you'll be really happy either way. Apparently the tri-ax is slightly louder, thats why i chose the 5.0. i love it.
I have the pro 5.0 and I like it a lot , But when I went to install I had to jack the car up and knock the old shifter off because of that stupid sealing stuff thats on it... it wouldnt come off for the world. It still only took me about 45 minutes to install though. Look here for an installation overview of the pro 5.0 it should be the same to install the tri-ax http://mustangworld.com/ourpics/fcar/shift1.htm
Well I have the tri-ax and I like the lower position. I think with any short throw shifter you'll be happy over stock. It is just all personal preference
I have the tri-ax and i love it...i didnt notice it being louder than the stock one. As for intalation, its easy took me about an hour and i never did it before. The toughest part was getting that stock shifter out, do everything right and the new one fits in great. either one youll love it because the stock one is suck crapp!