On the subject of FMUs, they are fine for small increases in boost like for low boost supercharger or turbo kits and even small nitrous shots where the fuel curve resembles stock. But when you start using turbos that can more then double your HP you are pressing your luck. Turbos change the VE of the motor and the bigger it is the further it gets from the stock maps in the ECU.
So cheap out on the exhaust, the intake, the downpipe, even the turbo itself but don't cheap out on the tuning.
