Orrrr go and buy something like this instead...
http://m.gumtree.com.au/v?adId=1024431610
Better brakes, gearbox, engine etc etc.
Plus it's actually an STI so will have better resale and you can actually insure it for what it is worth.
Only thing I would do is get an aftermarket
ECU and get it tuned properly (and possibly switch back to a good quality TMIC, like a process west or GD STI top mount)
Way better way to drop 15k than the OP's suggestion
Edit: just realized it isn't a real STI. However would still buy this over what the OP is talking about.