there arent many other mods you need for that level, basically just a turbo
fuel pump is just a walbro 255, injectors are sub 600 iirc, exhaust you can get 2nd hand, 3p solenoid ~$115, intercooler pipes well they arent so cheap brand new from my brief look, e85 tune - talk to beeble.
depends what model you want, a 7 isnt much more than an s15 for ones with a couple mods.