you need to think long and hard about your overall plan for your ms3, because some parts you may not want to initially get if you are truly going to go with a different turbo
case-in-point, if your plan is to get a bigger turbo, you are going to want to get a front mount. it will just end up being better in terms of consistancy and overall cooling capabilities
as for your "initial" parts...you can't really do it that way. you're going to end up getting rid of more stuff as you go along because they don't match up with what you're trying to ultimiately achieve
for starters, there is no need for an upgraded cbe. the stock one flows plenty. as for the rest of the exhaust, there is always power to be had by changing out the downpipe, and getting higher flow cats
the intake side is very restrictive when stock. but essentially, any intake other than stock will yield the same amount of gain in power be it sri or cai
other than the non-power adding bolt-on's, the last thing you would need is some sort of tuning. if you are really going to be going to a new turbo, get the cobb ap. but be forwarned, if you don't know what you're doing with tuning, don't do it yourself. don't **** with the AFRs on a turbo car without knowing what you're doing. take it to a shop where you can tell them your specific application for the vehicle and they can tune accordingly
hope it helps...because i really could have said "do a search you ******* noob" and no one would have argued against me because this has been discussed infinity times. but im only half a dickhead so i didn't start a reply with that statement
and i've been drinking