2008 BMW 135i

Current Mileage: 8981

We had no say in the fact that our 135i arrived to us on run-flat tires, and neither will you if you buy one. Run-flats are standard issue on the 1-series (and most other new BMWs, for that matter), and while they eliminate the need for a spare wheel and tire, they also have their own inherent drawbacks, namely in noise and ride quality. We've always felt the car's standard Bridgestone RE050 performance tires were a bit noisy, especially in the past few weeks as the rear treads have become noticeably thinner. The tires have also exhibited a dislike for small, first-order pavement imperfections, transmitting them sharply to the body. Most of that has been eradicated now, since we've changed over to conventional performance tires on a new set of aftermarket wheels.

We say "most" because the new rubber, Yokohama's new S.drive summer-performance offering, is considerably quieter than our set of Bridgestones on regular tarmac. But the Yokos sing louder than the Bridgestones on the concrete roads that make up a decent portion of the suburban-Chicago expressway network. Tread design is the most likely culprit, though the actual rubber compound may also contribute to this phenomenon. Those first-order thumps are now absorbed by the more forgiving sidewalls, but the tradeoff is a more isolated steering response. For everyday living, the Yokohamas are far more agreeable, though the factory-fitted Bridgestones actually embrace the needs of the serious driving enthusiast a bit better.

Our decision to change wheels was made partly for aesthetic reasons, but also to eliminate some unwanted weight, thereby freeing up some additional performance. We chose a set of Breyton GTS-R alloys in the original staggered sizes (18x7.5 in front, 18x8.5 in back). The GTS-Rs are finished in a matte graphite color, perfectly masking the prodigious brake dust the 135i seems to generate by merely starting the car, and feature a red accent stripe on an inner lip behind the spokes for a little visual drama. When we last visited The Tire Rack, their displays were filled with wheels of all sorts of colors and accents, and we thought the GTS-Rs classed up the 135i. You are free to disagree.

More important than the looks, however, is the fact that by changing the wheels and tires, we've shaved 35 pounds off the car. And while 35 pounds may not seem like a lot, the fact that it's all unsprung, rolling mass translates into an increase of performance on all fronts — acceleration, braking, and handling. Our efforts to quantify the gains were fruitless, as the car refused to hook up for a better 0-to-60 launch than our previous best of 4.9 seconds. We'll let the new tires scuff in a bit more and sharpen our launch-control sequence before we strap the vBox back on it.

Aside from the new shoes, the 135i has consumed another quart of Mobil1 at 8900 miles. The service indicator now tells us we'll need to visit the dealership before 15,000 miles rolls around, instead of the previous suggestion of 18,000. We got our oil analysis back from Blackstone Laboratories, and the report was generally healthy. Normal break-in deposits of aluminum, copper, iron, and other metals are present, but more importantly, the oil's additives are still present and active despite the miles. Still, we'll schedule a service visit soon and start over with some fresh lube.

The 135i has become the preferred vehicle for office lunch runs and weekend checkouts. Fuel economy has dropped to 19.6 mpg overall, mainly because it's nearly impossible to unglue our feet from the throttle; this car is the definition of driving fun. By the next installment, we'll have fitted an entirely new suspension and will have it to the track for some serious driving as well.



2007 Audi S6

Current Mileage: 17,361

There are sexier cars in the Audi fleet, but few are more masculine than the S6 (we'll grant you the R8). Part executive cruiser (especially in Mafioso black), part muscle sedan with that burly V-10, the only cougar you'll find driving one is likely a spiteful ex-wife who's won it in her divorce settlement.

Life with the S6 remains highly enjoyable at the wheel, although with oil setting new record highs every day, we're feeling a little guilty every time we coax that mill into 10-part harmony. A day at the dealership for service was also a fairly painful reminder of the costs that come with a car of this caliber.

Having hit 15,000 miles, it was time for the first major round of scheduled maintenance at Audi of Tysons Corner in Virginia. The process included replacement of our S6's oil filter, air filter, pollen filter, and Mobil1 synthetic oil. While there, we had them swap out the winter tires for Continental Sport Contact 2 summers, which added another $168 to our final tally. The dealership took advantage of our visit to re-flash the ECM according to a standing recall. We also had them look into our intermittent passenger-window issue and a new problem — an always-empty fuel gauge (our feet are heavy, but not heavy enough to send the needle to E upon every start). Both bugs were due to bad senders and were replaced under warranty. At $800.14, this was not a cheap trip; it made an excellent argument in favor of choosing the prepaid service option from Audi since the company no longer includes routine maintenance as standard.

Since its scheduled visit to the dealer, the S6 has performed flawlessly, whether stuck in traffic near DC or on weekend trips. It has tackled the beaches of North Carolina's Outer Banks and posed as a mafia don's ride in Atlantic City. In our East Coast office, it is the choice car to take for a weekend road trip, so long as you don't mind the eighty-dollar toll every time you fill up.