He may actually have a frame with oil... In the US they only imported 03-04 SXC's which I have and they lack the quart in the frame reservoir some European and Australian bikes do. He mentioned the word Carnet so Im assuming he is not from North America I have used both the 18 ltr and 28 ltr (actually I use the 2001 adv tank which has a 30 ltr) and for what you plan I would go with (if you can find it) the 28 liter hardpart acerbis tank. Skip the faring but if you have to then you will have to get the carrier parts and weld a bracket on the head tube then use a oem 28 tank and adventure faring. as far as wheels Just buy the 02 LC4 OEM cush wheel complete (and carrier)with the wider DID Dirtstar 2.50 rim . Keep your front .. respring both front and rear.