The Ford Mustang has held court in the modern day muscle car segment long enough. At least that's what Chevy and Dodge would like you to believe, as both brands are prepping their answer to the Mustang as we speak. Dodge's offering will of course be the new Challenger, and Allpar.com has dug up some news on the rear-wheel-drive muscle car's productions specs that was previously unknown. Along with detail information on each of the Challenger's drivetrains, including engines, transmissions and axle ratios, Allpar.com reveals two new features that the Challenger will sport when it goes on sale sometime next year as a 2009 model. The first is the same Hill Start Assist technology used on the Dodge Ram, Jeep Commander, Grand Cherokee and Liberty. Like the name suggests, HSA will hold the car in place on a hill, giving the driver a small amount of time to switch pedals and begin applying throttle. Hopefully it will save a few rear bumpers from some expensive bodywork. The second feature is called the Trak Pak, which is reportedly just a marketing term for a specific combination of transmission, shfiter and gearing. Available on R/T and SRT-8 models, the Tremec 6-speed manual is included, as well as a limited slip differential, though the axle ratio appears to vary between the two models on which the Trak Pak is included.