Yes you could if you really wanted to the bolt hole locations and size are the same as stock. The stock handle is the majority of the problem with the stock shifter so I would not recommend you doing this.
Yes, center-to-center on the holes is the same but you will lose a good bit of the precision. The stock shifter handle has large rubber bushings with steel inserts, very cushiony but sloppy compared to aftermarket without bushings. You will lose feel but it will also abate some vibration (very minor amount, not worth it to me)
Get the MGW handle, adjustable in height and tilt left/right-front/back.
Pro 50 has bushings available for this purpose. it eliminates all the rubber of the stock handle.. Why do we have two 50 shifter threads? I just typed this in the other one
The reason i ask is because without the stock handle i think i will have troulble reaching 3rd. The stock handle moves the reach back vs. the 5.0 shifter handle the moves the reach up. I don't see why the stock handle whould cause any shifting problems. The only problem i have is with the over all throw being so long. It seems the 5.0 shifter would eliminate that, but keeping the stock shift handle would stilll allow a comfortable shift.
I have no problems with the tri-ax shifter, but 3rd is a reach, I am also 6'4" tall. I usually don't shift to 3rd unless I am getting on it and usually sitting up in my seat at that time. Yesterday I was driving around with a friend of mine doing some work and towards the end of the day he started laughing that I had not gone into 3rd or 5th once the whole day. I don't even think about it but subconsciously go 1,2,4,6 when I am normally driving my car. I was driving normally and thinking about what he said and still skip'd 3rd without realizing it.
I have a Pro 50 Shifter in my Cobra but really did not care for the short upright handle that came with it,so i called steeda and ordered there tri-ax handle and installed it today and i like it so much better now.I highly reccommend this handle or the mgw handle to whatever shifter you decide to go with.