M1 prototype spotted doing some testing on public roads in Germany. BMW has confirmed an M version of the 1-Series based on the 135i is in the works. Power is expected to be somewhere substantially north of 330 PS (243 kW)

More spy shots have emerged of the upcoming BMW 1-Series M model.

This set of pics here show the camouflaged 1-Series M sporting a new quad-exhaust set-up. The quad-exhaust is a signature of BMW's M division models. Earlier spy shots showed a 1-Series M prototype doing some testing at the Nurburgring circuit. These latest shots capture the 1er M prowling the streets somewhere in the south of Germany, learning the ways of driving on public roads.

We've previously reported that M division Managing Director Dr. Kay Segler confirmed that BMW was working on an M version of the 1-Series that will be based on the current 135i model. One can only assume that the power figure for the 1er M will be substantially more than the 240kW (322 bhp/ 326 PS) that comes with the Performance Power Kit enhanced 135i.

So, how much power can we expect out of the compact 1-Series? Probably somewhere between 350 and 375 PS would be our guess.