could anyone please tell me what turbo this is and what is compatible with.
Genuine IHI Subaru GT555 (TD05H-16G-7)

Forced Preformance 16G. Should bolt right on to your car in place of the stock turbo. Check out this link, it lists a lot of turbos that are subie compatible. The FP 16G is a few posts down but should give you all the info you need.

http://forums.nasioc.com/forums/showthread.php?t=1141476&highlight=quick+spooling+turbo

Also check out the Deadbolt 16G a little further down. Its just about the same thing but the company gives a lifetime of free rebuilds. Either are popular upgrades, I'm looking into picking one up myself.