Help- Thinking Of Buying A 1994 Twin Turbo Estate

[vettec4]

Hello
I hope you can help me, I have been looking at Legacy Twin Turbos for a couple of months, and I think I will buy one this week.
But I have a few questions which I hope that can be answered.
1/ The cars I am looking at are Jap imports (hence twin turbo) I think they are called GTs?, are they known by any other name.
2/What is the spares situation and is the engine the same as any others in the Subaru range ie Impreza ?
3/ I have not driven one, but the people I speak to who have the cars for sell, say they drive great but are not very fast. (Performance is not that important, but I would like to know what to expect, (I own a 1995 Audi A6 2.6 auto at the moment about 160hp I think).
4/ Any weak areas with these cars which I should look out for when viewing.
Thanks for any help, as I have spent ages looking on the internet, and am very confused about these cars..