I'll have to keep an eye out for your car when i'm travelling as I spend a lot of time a couple of hours north of you. Looks brilliant in red, only thing i'd probably change is the wheels just for something slightly bigger but thats personal choice.

Hope you get your issue sorted, I personally think it sounds like the turbos making way too much air for the fuel system to keep up with, that turbo won't come alive till quite high up the range when you'd really start to notice it leaning out. I'd check the loom for the fuel pump and that the pump can keep up. Then get it mapped for the turbo.