Like 1 Bad Mirada said, the SRT model takes the performance of the Hemi to another level. The 5.7 has 345 hp @5,600 rpm with 375 ft/lbs torque @4,400 rpm. (due to increased compression ratio from 9.6-to-1 to 10.3-to-1, high-flow cylinder heads, and a more aggressive camshaft). The numbers for the 6.1 are: 425 hp @6,000 rpm and 420 ft/lbs torque @4,800 rpm. This results in 13.6 sec. 1/4s @105 mph and 0-60 mph @5.3 sec.

The SRT models also have 20" SRT wheels, 245/40ZR20 tires, 14.1" Brembo anti-lock braking system, specially calibrated springs, independent four-wheel suspension, upgraded front and rear sway bars, upgraded bushings, stabilizer bars, sturdier prop shaft, beefier rear differential, stronger axles, deeper exhaust note (2.8" pipes), cold-air induction, SRT-styled seats with oversized side bolsters, etc.

For what you get- an exclusive car that goes and handles- the additional $6,000 cost over an R/T model is well worth it.

To read up on the Hemis, see:

http://www.allpar.com/mopar/new-mopar-hemi.html