Current M3 last of the NA breed

BMW brass signaled the marketplace as far back as 2008 that the M division planned to ditch its trademark high-revving, naturally aspirated (NA) powerplants in favor of smaller-displacement turbo engines.

The transition from NA to forced induction (FI) began when the 4.4 liter turbo V-8 showed up in the X5 M and X6 M. While some loyalists wince at the notion of the revered M logo gracing the rumps of an SUV and a crossover, the choice of powerplants is a secondary issue: after all, any BMW model beginning with an X couldn’t be a “real” M anyway, so whether there’s a tradition-busting turbo mill under the hood is moot. The XMs are undeniably entertaining alternatives to mainstream trucks and crossovers, but they’re 2nd cousins to bona fide, pavement-snorting Ms.

E9x 8300 RPM redline is destined to disappear

When the 1 Series M Coupe launched with a 335-hp variant of the N54 inline-6 Turbo, more than a few M cognoscenti applauded the concept of a quick, taut 1 Series, but quietly lamented that a 3300 pound 3-series chassis in a 1-series skirt is less loyal tothe E30 concept than the brand spin-doctors would have the marketplace believe. The 1986 E30 – produced to homologate the M3 for Group A Touring Car racing – was around 500 pounds lighter than the 1 Series M Coupe, and its S14 engine was never turbocharged from the factory in standard, Evolution or Sport Evolution variations.

With the 2012 M5 “concept car” that appeared at the Shanghai auto show in May – followed by a formal coming out at Frankfurt in September – the march towards a turbocharged future continues. As expected, the M5 (and presumably its waiting-in-the-wings M6 stable mate) will be powered by a variant of the turbo V-8 in the X Ms.

This leaves the current M3 with its NA 414 hp 4.0 liter V-8 as the last link to the M heritage of high-revving, high-horsepower specialty cars whose powerplants aren’t shared with lesser brethren. While BMW’s primary justifications for embracing turbos – greater fuel efficiency and emissions friendliness – are difficult to fault on their technical merits, turbocharging Ms takes the sub-brand into a different realm. The approach allows BMW to continue to offer buyers a differentiated line of high horsepower, high cachet, relatively fuel efficient halo cars that will help the manufacturer meet increasingly high CAFE requirements.

From gjunkies’ perspective – setting aside the debate whether turbocharged engines are at odds with the M ethos – the last non-turbo M cars that qualify as sports cars (the E46 and E9x) are destined to be more desirable second-hand rides than any new, un-naturally aspirated models. (The future for E60/61 M5s and E63/64 M6s will play out differently. They’re complex and expensive cars to maintain, and once out of warranty their used values plunge. Buyers attracted to cheap M5s and M6s will face steep maintenance and repair bills as the cars age, and if history is a guide, many will defer needed work. A market awash with poorly maintained cars drives average used values further into an apparent “bargain” zone, attracting buyers even less able and willing to feed the cars a diet of expensive parts.)

The cold reality is that cost of owning and maintaining any BMW – especially Ms – out of warranty can be onerous, and needs to be weighed thoughtfully against the value of the ownership experience. As desirable as the 1 Series M and the future E9x M3 replacement will be when spanking new, adding turbocharging to the maintenance and reliability equation will tip the scales against future ownership of used, out-of-warranty examples.

Does it follow that the current M3 and the gracefully aging E46 M3 are destined to be recognized as the last, and best, of the non-turbo M breed? History may offer a clue: within a few years of Porsche abandoning its air-cooled tradition with the launch of the water-cooled 996 911 in 1999, the depreciation curve for late model 993s began tapering off dramatically. Today, air-cooled 993s occupy a special place in 911 lore, and a ’99 996 C2 sells for less than a clean, well cared for ’96 or ’97 C2. Which means getting an order in for one of the last E9x M3s produced (likely in 2012) could be the smart money move that also snags you a piece of history.