Short shifter and bushings, he'll love the feel of that and he'll never get tired of it. B&M if he wants to maintain stock height, twm and corksport if he wants it lower and even shorter. I had a B&M on my old p5 and was just a flick of the wrist.
I would recommend a short shifter...I have a kartboy (now corksport) and it's a cheap and great mod. You could probably get him that and something else small for $225.
smother shifts, its simple to do and it takes 10 min tops to do i think jacking the car up takes longer haha, i wish my parents would think about car stuff for me haha
If you want to get your son a short through shifter I have a TWM one for sale for much cheaper than a new one. Just click the second link in my signiture below to view it.