[krisr]

I find the opposite over this side of the pond. Fuel supply is actually quite easy and most get it right IF they spend the right dollars in the right areas. What brings most cars undone here is when people ONLY rely on the fuel side and don't let the ECU handle the spark side OR there is EMI noise, usually from poor or not well planned wiring, that creates issues with sensors or causes the ECU to reset and do silly things like that - or the tuner is just horrible and doesn't understand true modelling and just relies on closed loop.