BimmerWorld is working on one to complement their Sunbelt cams. Basically, the M50 manifold for e36 is good enough, unless you're making 280+ WHP ... after that, the M50 and throttle body start to become a bottleneck. The one you've seen is likely the Schrick one, and it's apparently a good upgrade for an M52/S52, abut is useless for M50/S50.
Now if you're talking about an ITB setup, like the euro motor, then that might be pretty cool to have, but still usless unless you're making huge power.
2007 BMW 328Xi Touring, 6 speed