Click above for high-res gallery of BMW X5 M and X6 M spy shots

Despite earlier assertions to the contrary, all indications are now that BMW is preparing its first batch of M-tuned sport-utilities, including an X5 M and X6 M. Advanced-stage test mules for both have now been spied by a keen photographer right here in the United States, at BMW's Performance Center test track in Spartanburg, South Carolina.

The prototype X5 and X6 M have enlarged air intakes with white LED headlamps up front and aerodynamic rear bumpers with quad pipes poking out the back. The trademark M division side gills have been camouflaged, but the exhaust notes are a reported dead giveaway: the X5 M prototype sounding like a twin-turbo V8, while the X6 M sounds more like a V10 or V12. The appearance of the M-tuned crossovers on American soil instead of on the Nurburgring gives us an idea of just who BMW will be targeting with these performance sport-utes. Check out all the spy shots in our gallery below and hit up the source for two spy videos. Mad props to PalBay for the tip and the shots!