i would get the cobb intake, and would stick with a turbo back all from one brand. i like invidia and cobb. with the cobb ap you dont need a professional tune they have maps that fit with those mods, gauges are always good to have, would go with a boost gauge, and an air/fuel gauge. for those mods thats all you really need. go on the cobb website or give them a call.
I just installed new cobb front and rear shifter bushings. It really tightened up the the shifting into gear but still has a fair amount of side to side slop. It was pretty easy and gives it a nice feel.
As far as intke, I am leaving mine stock but you do get much higher power gains with and upgraded intake. Here are the notes and data from COBB
I got a full turbo back exhaust from Turboxs, and an AEM cold air intake. Great products. Also got a Cobb tunning kit, works wonders. I'm not sure what else I should do/get?.?.?. Did install short shifter from Cobb and front and rear bushings. Any comments, I would really appreciate. Thanks!