This crisply styled mid-size crossover sport-utility vehicle is built off the same platform as the rear-drive CTS and STS sports sedans. For 2007, the SRX gets an updated interior, new Sport Package with 20-inch wheels and limited-slip axle, Bose 5.1 Digital Surround sound option (base models get upgraded to a newly standard Bose system) and new six-speed automatic transmission on models equipped with the optional 4.6-liter, 320-horsepower Northstar V-8 engine. A 3.6 liter, 260 horsepower V-6 is the standard engine in SRX — teamed with a five-speed automatic. SRX is available in either rear-wheel-drive or all-wheel-drive formats. GM’s StabiliTrak electronic stability system comes standard; Magnetic Ride Control is optional. The SRX’s interior can hold as many as seven passengers with the optional power-folding third-row seat. A navigation system is standard on the V-8 version and is optional with the V-6. The Sport Package includes front and rear sport fascias, new body-colored grille with V-Series-style mesh backing, 4-inch dual polished exhaust tips, the six-speed automatic transmission with Driver Shift control and optional 20-inch Sport wheels with high-performance tires. The airbag system in the SRX has been upgraded with weight-and-size sensing Passenger Side Inflatable Restraint (PSIR) suppression; this feature uses sensors to detect the occupant’s size and enable or disable the air bag automatically. OnStar-equipped models also get turn-by-turn navigation assistance.