Yes Alpina seems to overate their stuff. Evidenced by the B7 test recently against audi. It did not even make stated hp and lost badly to the audi.
The current m3 would outdo this new B3 let alone the upcoming m3. The current M3 has been tested at 3.9 to 60 but more commonly 4.2. 12.5 in the quarter.
I would have thought alpina would have went for 450.
I personally would never bother with alpina. I truly think their concept is becoming irrelevent with modern bmw's
1.New bimmers are getting so comfortable and relatively soft and luxuriuos that there is much less of a need or desire to get alpina for the added luxury they used to provide over stock. Still is improved but not nearly as much as it once was
2.With EDC and adaptable suspension, it makes no sense not to by the equivelent M model as you can now make M cars as soft as you want. The alpina used to sell the fact the M was more hardcore and alpina was more comfortable cruiser. Not true anymore
3.They used to add FI to NA engines that really added a ton of value as that is a huge aftermarket endevour for someone to do on their own. They made a ton of hp over the equivelent OEM version. Now with turbo's the regular bimmer model makes big power or is so easily tuned to make big power that alpina's power numbers are no longer difficult to match.
I don't think alpina will last on the same level as they once did