Im running with the straight through header now. Its Type 2 if your using stock silencers.
Quoting Stuart at Spareshack:
Type 1 is two seperate pipes which were
really designed for use with a 2-1 silencer and type 2 has
the pipes joined together with a cross over for the gas flow
which is the best option which the standard 2-2 set up
Havent done anything about fuelling. The sound is certainly a little louder and throatier, but at standstill its still the rattling clutch which attracts the attention!
How many miles you done now? I had my first service 5 days after I picked it up!