take a look at
www.protegegarage.com
they have good prices on side mount intercooler upgrades...that will give you some good gains right there
if you want a reliable car for daily driving:
smic upgrade
hardpipes
turbo back exhaust
that right there will naturally heighten your boost levels to the 8 psi range (and possibly a spike to 9, no biggie) and will be reliable
dont bother with an intake upgrade...the gains are extremely minimal...instead drop in a drop in filter...the intake sure does look nice and give a nice sound, but the gains are just really worth the cost (270ish new, much less used)...however, there are those that would argue the opposite as well, especially with a modded car *shrugs* theres a lot of oppinions on these things here
the one worry I would have (even when stock) is that the LSD will fail on you eventually, just be ready in case that happens...and if it does replace it with a welded LSD or a Quaife LSD, both work just fine....if you mod the car I wouldn't say it will accellerate its happening, but it cant help it either, ya know?
aside from that though you shouldnt have any problems with the mod list above, if you want to take it to the next level then I would recommend getting a unichip...its plug and play (no wire soldering involved at all) and gives good gains with the mods above (dont use the boost controller though, most will spike to 14 and thats no good), however it is not as easy to get it tuned cause its gotta get tuned by a unichip-certified shop that has the right software
anywho, that being said...good luck!
more sites of interest:
www.*************.com
www.speedcircuit.net
www.empiretuning.com (shoot them a message if you dont see what you are looking for on their site, chances are they can get it and Eric is a cool guy)