After long drives in both the Dodge Nitro SLT 4WD and R/T 2WD, we prefer the R/T.
The 3.7-liter engine in the SLT is slightly harsh and too slow, and the four-speed automatic transmission needs another gear. When we floored the SLT once at 40 mph, the transmission didn't kick down and the vehicle felt gutless. The suspension takes bumps with a jolt, especially at lower speeds and mostly at the front wheels. And when we turned off the stability control and drove it aggressively around a hairpin turn, the front end washed out as badly as anything we've felt in a long time, on its Goodyear Wrangler on/off-road performance tires. This was surprising, because the Nitro is a rear-wheel-drive platform.
Dodge R/T models are considered high performance, but in this case it's not hot-rod performance, it's simply a higher level of basic performance by the engine, transmission and suspension.
The 4.0-liter V6 is a single overhead-cam engine. It's rated at 260 horsepower, 50 more than the engine in the SLT, and it provides 265 pound-feet of torque at 4200 rpm. That's a lot of horsepower and torque, and we can't say that the R/T really feels like it has that much; but we can say that it accelerates up to 90 mph without messing around. Both engines can tow up to 5,000 pounds when equipped with the towing package.
The R/T engine is quieter than the 3.7-liter in the SLT, and it gets nearly the same mileage: 16/21 mpg EPA City/Highway with 2WD, with 89 octane recommended but 87 acceptable. We got 16.7 mpg driving the R/T very hard out in the country.
The five-speed automatic transmission makes a world of difference in smoothness over the four-speed. However in manual mode, it doesn't listen. It only responds to a shift by the driver (at least this driver) about half the time. Most of the shifts to which it doesn't respond are about saving gas. It refuses to short-shift, or upshift before redline under heavy throttle. Nor will it upshift when you back off the throttle. As a result, passing on two-lanes is unnecessarily difficult. The upshifts near redline (6000 rpm) are slow, not as sharp as one might expect from an R/T. And the shift mechanism is not ergonomic; that is, the shifts are made by moving the lever from side to side, not forward and back, which would be easier.
When the Nitro was released in 2007, it seemed like an old school, 1990s-style SUV with a truck ride compared to the slew of carlike crossover SUVs we've been getting. Perhaps in response to those criticisms, Dodge has retuned the suspension, steering and brakes for 2009 to improve the Nitro's handling and braking. While those changes make the Nitro a bit more precise in its movements, a leopard can't change its spots. The Nitro still has a bouncy, truck-like ride, despite its unibody construction, and the tall, top heavy design makes it lean in turns. The handling of the R/T is reasonably sure-footed, and considerably more precise than the SLT; Goodyear Eagle tires help a lot. Surprisingly, we found the R/T's ride to be better than the SLT's. Theoretically, the R/T's tuned suspension should be firmer, and surely it is overall, but it's also more comfortable; yet another reason the R/T is better than the lesser models.