Here's the list....
Series McRae - '95 (UK RHD)
"555" special edition - '95 (Europe LHD)
Catalunya Special edition - '96/'97 (RHD & LHD)
Terzo special edition - '98 (Europe LHD)
STi 22B - '98 (Japan/UK RHD)
Club Spec Evo2 (Aust.) - '98 (Aust. RHD)
RB5 (Richard Burns edition) - '99 (UK RHD)
Prodrive P1 - '99/'00 (UK RHD)
Prodrive UK300 - '01/'02 (UK RHD)
Try this site to learn everything you ever wanted to know about the Impreza... from the BEGINNING!
http://www.sidc.co.uk/faq.htm