My understanding of the old L6/L8 is that you can not change the duty cycle of the injector as you can with modern ecu's. Which I thought meant that when you put 1000cc injectors on the older management, at idle and until you're on Boost you get heavy overfuelling. The new managements allow you to change the amount of fuel an injector delivers throughout the rev range giving you a much better burn. I'm sure someone will correct me if I've got this wrong!