The E90 began production in May 2005 as a 2006 model. Currently, four engine options are offered, two being part of the new 'N' series of BMW inline engines featuring a lightweight magnesium/aluminum construction and technological innovations such as individual cylinder throttles, steplessly variable valve timing, and dual stage intake timing. The 3-Series is manufactured in Regensburg, Munich, and Leipzig, Germany while only the coupe, convertible, and some sedans are manufactured in Regensburg. The E91 touring model has also been available since fall 2005 along with 4WD models 325xi, 330xi and 330xd. The E92 2-door will come out in September of 2006 along with BMW's new N54 twin-turbo engine.