looks like the slr needs the front spoiler to do it

ol math, weren't we taught to always round up anything .5 and above to the nearest whole number? Thought so. Therefore, the SLR McLaren, which reaches 199.5 mph at our 2-mile limit, qualifies as a 200-mph car in this test.

Sorry, we're more exact than that. On four separate runs, the supercharged carbon-chassis SLR blows past the 2-mile marker at a speed topping 199 mph. That's impressive consistency, if not quite the velocity we hoped to see. The sleek Mercedes with the hand-built supercharged V-8 launches quietly and with minimal wheelspin (Mercedes says it's best to leave the traction control on), but it's just not quite able to reach 200 in 2 miles, even though the SLR has a claimed top speed of 207 mph.

After two nearly identical runs (one letting the car shift automatically, the other using the shift buttons on the back of the steering wheel), Steve pulls back into the paddock. "The peak speed at 2 miles was about identical in each of those runs. My launch didn't seem like the best, but I don't think it makes much difference in overall speed. This car seems to get to 180 pretty quickly, then it takes another mile to reach 199."

Again, Steve is right. Our data show that at 1 mile, the SLR is traveling at 181.2 mph. Over the next mile — in a performance much like the Lambo's — the car gains only 18.6 mph. What's more, Steve complains that "at around 185 mph, the SLR starts to wander a wee bit. It gets your attention. It feels like it's packing air under its nose."

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He may be on to something. The Mercedes folks had fitted this SLR with 18-in. winter wheels thought to create less drag than the stock 19-in. ones, which have special blade-shape spokes that work as fans to extract air from under the car for added downforce. The 18s, they presumed, would have less drag because the car wouldn't be getting sucked closer to the ground. However, this means the nose of the car on 18s is likely higher, creating that feeling Steve noticed of air getting stuffed under the nose of the car.

After a couple more tries — this time shifting manually, with traction control off and switching from the Sport to Comfort suspension mode for added grip at the start — the SLR comes back each time at essentially the same speed. Lending further credence to Millen's belief, it's interesting to note that Mercedes fits the latest SLR, the 722, with a deeper carbon-fiber front splitter that increases front downforce by 128 percent at top speed. That new spoiler, we're fairly confident, would put this production SLR, a 2-year-old test car with 4000 miles, well above the 200-mph mark.

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