Originally Posted by Nick P

It's BS. There never were any S50 powered X5, especially in Gemany. I mean how such a BS can be published - it's obviously a kid's fantasy.

Another citation from the english X5 wiki-page

"The 4.6L V8 engine was developed by Alpina from the 4.4L V8. A sporty model badged 4.8is was also released a few years later replacing the 4.6 engine with a 4.8-litre (also developed by Alpina and used in Alpina Roadster V8, based on BMW E52 Z8). X5 4.8is was labelled "fastest SUV in the world"."

The autor doesn't even know the engine types used in E53.

And the 4.6 M62 wasn't developed by Alpina, it was BMW's own work, sure on paper they're identical but I assure no one Alpina worker was officially involved in the developement of the 4.6is engine.

Alpina also used the 4.8 l version of M62 in the Z8 and E39 B10S (same bore as 4.6 but S62 crank), not N62.