Um my guess is a bit higher than 330bhp as BMW seems to be taking the fight to S models etc with M performance line.
Merc are looking at 360+ BHP for new AMG sport
http://www.autoexpress.co.uk/mercede...rce=newsletter
Audi S4 2015 is rumoured to be 350+ BHP
http://www.autoexpress.co.uk/audi/a4...te-and-rumours
As for a PPK to reach the same output as their competitors' S and AMGSp models I would say that's not good business sense - it says subtly that your product is inferior from the outset. Maybe one for the M3/4 to compete with C63S might make sense.
As for the BHP of 340i vs the M3 it's surely the torque difference that's crucial there, and that the M3 is highly underrated.