By Andrew Ganz
Monday, May 10th, 2010 @ 3:00 pm

BMW has long had great success with convertible variants of its high-performance M-badged cars – like the M3 and M6 – so it should come as little surprise that the German automaker has apparently green-lighted an open top version of its upcoming 1-Series M sports coupe.
Our rendering, compiled using tips from BMW insiders, has been described as “on the money” by those in Munich. These illustrations show the widebody-style fenders, front fender vents and sculpted sideskirts that BMW’s Motorsports division has painstakingly crafted to help set the 1-Series M apart from its standard 135i brethren.

From the rear, you can see the new ducktail-style boot spoiler, unique diffuser and special side vents. The 18-inch alloy wheels are M-specific, too. The M-style quad exhaust in our photos may or may not make it to production, however. BMW’s Motorsports gurus are apparently debating if the extra weight of the now-signature exhaust style is worthwhile on the small 1-Series M.

Expected to be powered by a turbocharged inline-six cylinder engine, the 1-Series M will certainly best the already quick 135i. Specifics are among Munich’s closest-guarded secrets, but insiders told us to expect around 330 horsepower – a 30 pony jump from the 135i. But more important will be dialed in handling and a reduced curb weight, both of which should make the 1-Series M a true hot rod.

As for a more official name: Even that appears to be still under debate in Munich. Sources indicated to Leftlane that the car won’t use the revered M1 tag that once defined the wedgy late ’70s supercar that heralded the M Division. Instead, M Turbo and 1M Turbo are reportedly the front runners. For now, we’ll just call it the 1-Series M.

Don’t look for a five-door hatchback 1-Series M in Europe. BMW has never had much success marketing a four-door version of its M3 anywhere and it looks like coupe and convertible versions will be the only options for the new model.