There's plenty of spring in the Nitro R/T's new 4.0-liter engine, and with a five-speed automatic handing out gears, power delivery is nicely done. Jumping on the throttle in the R/T elicited a slight hesitation, but the Nitro regained its enthusiasm quickly, responding smoothly throughout a torquey power band. Throttle tip-in was a little abrupt, and brakes were responsive but spongy. A casual stopping test showed the Nitro to be above average, distance-wise. Our biggest complaint was that for an R/T trim, the transmission ratios seemed chosen to save gas. The Nitro struggled while driving uphill and passing; we concluded that the transmission could be better geared to make the most of the powerful engine.