Welcome to the community,
It sounds like you've got just a rolling chasis, which if the engine is in good shape is well worth the 1800 dollars. Does it need all those parts because of an accident? is the frame straight? How many miles are on it? Does it run well?
The 03 was the last year of the bug eye, and there are a ton of aftermarket parts as far as bumpers and hood and trunk so you can go crazy if you've got the money. 1st thing I would do is get an alignment, If its within normal parameters that means that the frame is straight and its worth building up if not you might have opened a can of worms. Depending on your budget you can get some decent prices on used ( read : road rashed ) OEM parts on ebay. For a bit more than a grand you can probably replace all the body panels you mentioned. Then take it to a body shop and have them paint it an OEM color.
Good luck with your Subaru
See you on the road.
13 WRX Hatch - Cobb OTS Stage 1