It's not until late in our cross-country test bash that the defining differences between the 2008 BMW 135i, 2008 BMW 335i and our long-term 2002 BMW M3 become crucial. We're vectoring along California State Highway 190 approaching Death Valley and climbing to the 4,963-foot summit of Towne Pass, and then the turbocharged 3.0-liter inline-6 engines of these 1 Series and 3 Series BMWs begin to carve out a decided advantage over the normally aspirated mill of the brilliant but aging M3.
The less frenetic acceleration of the current-generation cars becomes their most profound strength on this long, steep climb above 3,000 feet. Fewer gearshifts, more accessible power and a less demanding load on the driver are good when ripping across straight sections of desert road at barely sub-mach velocity.
But only a few hundred miles back, where the road was smooth and winding and the air was far denser, the M3 had been in its element. The questio