Short throw is the first thing I did to my past 2 cars. It makes shifting more pleasurable, and as far as install goes. It is remarkably easy to do, the shifter part takes about 30-40 mins, but bushings will take a little longer because you have to get under the car. Still not bad though, and I know my TWM short throw came with step by step instructions that made it super easy.
Go open source, it is cheaper and I have heard that it is just better all around.
CBE is just a noise maker, go quieter if at all. I like the SPT just because it sounds stockish but "sexier"
Intake or DP will require a tune, so if you get one of those it has to be tuned.