Well, I'd say understand which which EM option you want to go with. EM = Engine Management or tuning opion. Because these cars are pretty much mod and required to tune for the new parts on about 95% of the parts will put on the car. Its not a good idea to run mods without a tune a majority of the time...like a said. There are a few mods you could run while just limping the car around with no boost. But, who wants to do that?
378awhp/373wtq Custom Dom 3 & CBRD tuned 2006 STI.
"When in doubt...flat out" - Colin McRae