Its a common misconception that the 4.8is was an Alpina engine which it was not. Yes, the 4.6is was an Alpina engine from the B10. But the 4.8is engine was a standard engine from BMW 550/550i. People wrongly assume the 4.8is is Alpina because its a 4.8 like the B10 V8S which was also 4.8. But a little search reveals that they aint the same. Alpina used a highly tuned and modified M62 and 4.8is used N62B48. Look at the tech spec, the engine size, bore, compression ration, etc are all different.