In fact 320 is not bhp, it is PS! Like 1M is 340 PS but 335 bhp or hp. M135i has 320 PS or 315 bhp/hp.
Using kW as the only power unit would avoid these common confusions but...
Here is one of the good converting tools:
http://www.which.co.uk/cars/driving/...wer-converter/
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"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
BMW 1M-SOLD-: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, BMS OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake.