Hi yes its AHU underneath and tried to keep it as OEM as possible but I much prefer the mk4 cover as it looks tidier. As for economy its mega cheap to run, did 280 miles on the weekend on 1/3'rd of a tank
also have a VNT conversion with a mapped ECU, 3 bar map and 2.5" exhaust to go on soon, along with a PD inlet and hopefully a ported head