BMW is working on a new range-topper for its latest 2012 1-Series Hatchback model sold overseas, a prototype of which has been spotted testing at Germany’s Nürburgring and on some of the race track’s surrounding streets.

That new range-topper is the potent 135i model, which is set to debut in Europe later this year along with a new three-door bodystyle for the 1-Series Hatchback (currently only the five-door is available).

As its name suggests, the 135i prototype seen here is likely to be packing BMW’s latest ‘N55’ 3.0-liter straight-six engine complete with 300 horsepower and 300 pound-feet of torque.

Considering this engine is capable of accelerating the bigger and heavier 3-Series from 0-60 mph in just 5.4 seconds, we expect that the 135i will be able to cover the same benchmark in around 5.0 seconds or less.

Unfortunately for us, the latest 2012 1-Series Hatchback--including this 135i variant--is unlikely to be launched in the U.S. That's a shame, though all is not lost as the drivetrain in this car will feature in range-topping variants of the next-generation 1-Series Coupe and Convertible models, which are due next year and may be called a 2-Series.

The story doesn’t end there, however, as an M Performance version of the 1-Series Hatchback is also planned, previewed by the 320-horsepower M135i Concept unveiled at the 2011 Geneva Motor Show. These get a little extra power plus M-tuned handling packs, stylish bodykits and sporty interior trim. Hopefully, the two-door versions of the latest 1-Series will get the M Performance treatment as well.