I found this post from GTSPIRIT - Gumball 3000, Bullrun, Cannonball & MORE to be pretty informative:

Finally BMW makes competion for the E55 AMG Break. Powered by the same 5.0-litre V-10 cylinder engine as its Saloon brother, the new M5 Touring has a max of 8,250 rpm. 507hp and 520Nm of torque make the car go from zero to 62mph in 4.8 seconds which is only 0.1 seconds slower than the normal M5. This can get worlds largest and fastest cargo car.

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[via Carscoop]

Found at: GTSPIRIT - Gumball 3000, Bullrun, Cannonball & MORE