The GTN had the Alpina 4.6 V8 from the BMW X5 4.6is and various Alpina products; therefore, this does fit and can be wired into the S1.
However, the E39 M5 uses the BMW S62 engine, which is a derivative of the M62; more information on the S62 can be
found here .
My concern would be the size of the engine and as the others have said, the complexity of setting up the electronics.
