Cool times Mr. 10secdodge. I'm a 2006 Mustang owner but possibly sooon to be a Challenger R/t 6spd owner as well (not giving up the "Stang"). With my short test drives of the R/Ts, the weight and the feel of the weight of the Challengers did not lead me to belive they were capable of those times but I won't harsh on you. Your experience at the strip definitely counts for something. I just hope I can get that deep in the 13's when I get a chance to take the R/T to the track.

Back to the axle question. Autos only get the 3.06, no other options. Manuals come with the 3.72 and 18 inch rims. 20 inch rims on the manual get you the 3.92 gears, a real limitted slip diff and a traction control switch that will turn it completely off.