its no problem bro... the extra plug is for the Auto tranny portion of the harness at least it should be... I'll tell u what i used for my freinds swap... Car=USDM 2000 Civic DX hatch Manual Tranny(SOHC), Wiring Harness= USDM 99 Civic EX(SOHC) Manual Tranny, ECU= USDM 99-00 Civic SI(DOHC), Engine= USDM 1996 GSR, Intake manifold= Skunk 2, Throttle Cable= USDM 99 Civic SI(DOHC), Rear Motor Bracket= USDM 99-00 CIVIC SI(DOHC)... and thas pretty much it. Anyway lemme kno what the deal...laterz