2010 Cadillac CTS-V

Under their hoods, both M5 and CTS-V shiver with muscle, but here their recipes differ dramatically. The BMW's mill is the product of a Formula 1 clean room, a 5.0-liter V-10 fortified with a throttle body for each cylinder and an 8250-rpm redline -- enough for 100 horsepower per naturally aspirated liter (and 383 pound-feet of torque). The 2010 Cadillac CTS-V will have none of that exotica. Its engine is, essentially, a "lite" version of the LS9 in the Corvette ZR1, though it's about the weightiest "lite" you'll ever see. Ahead of the firewall lie 6.2 supercharged liters of V-8, good for 556 horsepower and 551 pound-feet -- and possibly a nod to power the next Space Shuttle.