There are a few ways to do it, I just used parts from a AEM and then used some custom piping I bought and cut. You can see pics in my build thread. The most important piece you need is the MAF housing and screens.
really depends on how low you want to go and what your budget is, if you're staying at stock height then a 9.5 or 10 with a decent offset will not be a problem. If you're going to be lowering the car any than fender rolling and tab shaving etc. come into play if you go super aggressive on offset. My understanding on the 9.5 is anything below 30 is beginning to push it, I have 19x9.5 +29 on the rear of mine and when the car is aired up the wheel sits pretty flush, it tucks in when aired out due to how the suspension works. I'm fixing to change all that soon to a static drop, should be a lot easier to deal with. If you have any specific question in mind feel free to ask, I know these cars pretty well after all the work I've put into mine lol