ok, hand holding time.
NASIOC has a healthy listing of Subaru Stuff.
Here's the New ENgland section "FOR SALE"
http://forums.nasioc.com/forums/forumdisplay.php?f=128
Here is the NASIOC national "FOR SALES"
I advise against getting an engine from far away. Shipping will be pricey.
http://forums.nasioc.com/forums/forumdisplay.php?f=9
Here is craigslist Maine
http://maine.craigslist.org/
Search under the auto parts section
Here is Uncle Henrys. Search auto accessories
http://www.unclehenrys.com/init/search/results/1
You might also try Norms Used Cars in Wiscasset. They specialize in Subaru cars and used parts.
http://www.normsusedcars.com/parts/index.htm
Also Lake Region Imports Does a lot of Subaru used cars, not so much used parts, but worth a call.
http://www.lakeregionimports2.com/joomla/
Best option is look in your yellow pages of the phone book under SALVAGE YARDS, AUTO RECYCLERS, Junk Yards, Used Auto Parts. You will find all kinds of listing of places you can call and they will have what you need or can locate what you need and get to their place ready for your pick up. Some places will offer warranty on some of their big items like engines.
Good luck. Buy local. If you need some one to throw that bad boy in for you I recommend inquiring with the vendors on this forum, MikeyMeyagi, or your local indy garage. Be nice to your Subaru and it will be nice to you.