Xoutpost.com - More changes to X5 M prototype

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BMW's high-performance X5 prototype hit the test track again, this time showing some interesting changes compared to earlier test vehicles. While prior prototypes had some styling changes, the headlight design remained pure X5. On this newest prototype, the headlights appear to have been switched out with X6 headlights.

This latest prototype also features a new rear treatment. Earlier prototypes used the standard X5 rear valance, mocked-up to accommodate its new M-style quad exhaust set-up. The X5 shot yesterday, however, gets a new, larger rear bumper that wraps around to the middle of the rear wheel well. The rear fascia on the new prototype looks like a more-finished production applicatin compared to the initial test mules.
This hotter X5 prototype still remains something of an enigma. Three scenarios have been suggested: Is it an X5 M, a new X5 5.0is, or is it a mule for a V-10-powered X6. The application of a new production-looking rear bumper lends credence to the argument for a hotter X5–most likely the new 5.0is. The addition of the X6's headlights muddies the waters a bit more. Will this sportier X5 adopt X6 headlights while lesser X5s keep their normal lights, or will all X5s get X6 front lamps as a mid-cycle facelift?
While we can't say with certainty exactly where the X5 lineup will head in the next two years, it's clear that this hotter X5-based prototype is progressing toward a more finished product."