You have to use all the B6 harnesses Except the fuel injection harness...you have to strip it off the b6 and put in onto your bp..
Also are you using a b6 Fseries manual trans or a bp gseries manual??
The Fseries(stock dohc) half-shaft doesn't quite fit and either needs modification or a 1996 dohc half-shaft and the stock outer axle..
If you plan on doing anything to the motor ... boost, headwork... and want to be able to tune it...Going to a EMU now would save u alottttt of time and some cash...
To get a full harness and ecu will be like 200bux..then later even megasquirt isn't cheap...and you still have to wire IT into your harness..
Getting a EMU now will cost 500-1500 but you'll save countless hours and headaches over splicing the BP ecu or changing the whole harness...