Walaikum Salam
Glad To Know Ur Buying a 3Gee
well, in Plaza, Nasir Autos is the place i buy parts for my accord, they have japanese aswell as parts from taiwan, prices are negotiable and not too high
Air filter costs arent high aswell, to avoid frequent change-ups, get ur air cleaner element cleaned by high pressure air (mostly found at fuel stations) regularly.
Engine Oil , well depends on the engine condition, engine oil level wont drop if ur car is in good condition, get Shell Helix or Castrol for best performance. keep a regular check on the dip-stick
Coming to the auto trans part, i myself have a Manual Tranny Accord , but a close friend of mine owns an Auto tranny accord, automatic transmissions in these cars can sometimes be a prob, but u can easily get parts from plaza or larger parts from Shershah
-i prefer u mate the transmission with a manual one, wont cost alot.
and please mention the demand of ur friend too, cheers mate