Good find! You can pick up a VF39 (sti turbo) used for $350. You can get an STI top mount intercooler for 200 ish. Look around the classifieds in iwst and nasioc. There’s stuff popping up all the time.
It sounds like that may be enough to get you going.
STi up pipes also don’t have a cat, so they are almost as good as an after market one. You can get used after market downpipes all day, but I recommend the Turbo XS belmouth pipe. If it helps, my stock downpipe is sitting in the garage. You are welcome to borrow it to assess the damage if it helps.