Again, just my understanding of these cars which is by no means omniscient, but there are some better options for the money for these cars.
For instance, intakes in general are pretty much useless on a mostly stock vehicle. You will see little to no gain, and sometimes even loss, from an intake and these cars WILL NOT run properly without a tune on an aftermarket intake. The best thing you can do for the ralliart is get a high flow drop in filter. You might notice a very small amount of increased throttle response, or not, but it does make the turbo much easier to hear spooling which is fun.
If you're going to be doing anything with the computer at all, have it be a real tune. Whether you go with a protune for $500, which is the best route, or use one of GSTs free base maps, and just lead your mods in the direction they desire you to. Those maps can be found here:
http://www.evolutionm.net/forums/09-...t-basemap.html
Just be very careful saving ROMs to your ECU. Make sure you do research before you make an attempt. And you'll need a Tactrix cable, or equivalent, to do it. (Sorry, not sure how much you know so I figured I'd say everything.)
And last but not least, a BOV isn't needed for this setup; however, the Ralliarts stock BOV really, really sucks. It's a tiny piece of crappy plastic. It's a really good idea, for maintaining boost levels properly, to upgrade it to either the stock Evo BPV, or get an aftermarket one. Just remember as cool as the stutututu is, these cars need to have recirculation especially for the SST, for reasons unknown to me, but the ECU is expecting it. Do not buy a single port BOV that vents to atmosphere or you'll be doing yourself a diservice down the road. Unless of course, again, you're just going to have it protuned.
When I get to work, I'll send ya a link from evolutionm.net that has a really great write up about where to start on these cars and why. It made me rethink my entire build idea.