2005 saw many changes, the most notable of which are the optional Tremec M10 or T56 (it's reported both ways) six-speed manual transmission and the new Generation IV 6 liter LS2 V8, with 390 horsepower and 405 lb-ft of torque. With those changes, 0-60 times dropped from a four-cylinder-style 7.6 seconds to a blistering 5.5 seconds (with automatic; 5.3 with stick). The quarter mile comes in under 14 seconds.
There's also a retuned steering system for better on-center feel and lower low-speed effort, a quasi-dual exhaust, dead pedal, new engine cover, self-supporting gas hood struts, and MP3 playback ability. New options include an auxiliary gauge package, windbreak, and body color paint on various internal surfaces. The new steering tuning includes retuned valves and torsion bars, a new bearing, and a low friction steering sealing package. Finally, the driver's side floor mat has been revised and Aqua Blur replaces Ultra Violet. the automatic is now the 4L65-E.
More effective and less restrictive catalytic converters are mounted closer to the exhaust manifold for quicker “lightoff” and reduced cold-start emissions.