It's difficult to increase horsepower in a big way without losing something on the bottom end of the torque curve. It's also difficult to enhance low-end torque without losing something at the top end. What if you could have it both ways? You can with supercharging.
Rimmer Engineering of Colorado Springs builds supercharger kits for Jeeps that claim a 30 percent increase in power and torque. Kits are available for 2.5L engines; 4.0L kits and 5.2L kits are close to completion. Owner Rick Rimmer has been in the forced-induction business since 1995, and he builds kits for a variety of cars, trucks, and 4x4s.
The beauty of these kits is that they don't negatively affect emissions, drivability, or economy. The benefits come right off idle, with boost coming in as soon as the throttle is opened. This greatly enhances low-end grunt, but the increases extend all the way to redline. (see the Forced Induction Primer sidebar for more details on how superchargers work.)
Eaton superchargers have a working life of approximately 100K miles and can be rebuilt. In fact, since Eaton blowers are used in some OEM applications (Buick, for example), an exchange program has been instituted to minimize delays. Since the impellers don't actually touch, the only wear occurs in the sealed bearings.