I have had both, the MGW and Tri-ax. I liked the adjustability of the MGW and the shift length, but I liked the Tri-ax for being a little crisper and faster.
MGW here, can't go wrong with either it or tri-ax. Should come from factory with short throw. First mod that should be done in my opinion. It makes a huge difference.
Tri-ax was the one I chose between it and the MGW. Heard great things about the MGW and a good choice as well. I chose the Tri-ax for its crispness and precise shifts because I autocross and don't like missing shifts. You wont be disappointed in either. Not recommending it, but most, even cheap, short shifters are better than the stock one.
I can't stand a stock shifter... I had a cheapo one in my old Mustang just kinda as a temporary thing cause I hated the stock one after I drove a Cobra with a good one... Even the cheap one was waaaaaaaaayyyyyy better than stock. Can't wait to get the insurance money from my wreck so I can put a short shifter in my new one.
There are a couple of websites with .pdf instructions that are a bit more clear and offers additional info. I just can't remember them.
You will have no problem and I know that you are going to enjoy it. Unfortunately I am waiting for April and some better weather before I can put my shifter through its paces.
My shifter is sitting on the work bench next to the car. Hopefully this weekend the car will come out. I've been missing out on the really early spring weather.