So the ALPINA version of the F30 has been revealed (http://www.f30post.com/forums/showthread.php?t=811899
The 0-60mph time is said to be 4.0 seconds (with AWD). Now, think of this: BMW says that the M5 can do it in 4.3 seconds, although during tests, the M5 has done it in 3.7 seconds.
How fast in a straight line will the B3 actually be? This might sound absurd, but imagine a 6 cylinder car blasting to 60mph in 3.5 seconds.
Also, ALPINA can't make the B3 faster than the next M3... The next M3/M4 will be a rocket.