For complete information you should purchase the following manuals from a Subaru dealer:
G170GE1 General Information Section
W170GE Mechanism and Function
G170GE2 Repair Section
G170GE3R Diagnostics Section
G170GE4R Wiring Diagram Section
G171GE4R Wiring Diagram Section SRS
G173GER 1994 Supplement (Contains Turbo Info)
This will cost about £130 and you may need some additional supplements as this only covers everthing upto MY95.