Seriously don't waste your money with closed loop, I have that feature on my aftermarket ecu emerald K3, but don't use it as if it is set up correctly/mapped isn't needed.
I can get 40mpg on a run no problem, best thing I ever did was ditch the L6, though it's not a bad ecu when live mapped, but all adds to cost, 3 maps on mine cost £280.
tabetha