Looking at the motorhome results, for example, the modified unit reached 60.969 mph in 23.164 seconds in the quarter mile while the stock unit came in at 58.159 mph in 23.441 seconds, giving the edge to the modified motorhome by 1.18%. And fuel economy on the two-day ride and drive proved 17.33% better on the modified chassis when compared to stock chassis NHRA champion Joe Amato (l) is greeted in Seattle by Bill Laughlin, general manager specialty products for Tenneco Automotive. Moving back to real-world conditions, RV News drove the various units for two days over a 346- mile route that took us in a loop east and south of Seattle returning to the coast near Salem, OR. After an overnight rest stop we headed back north ending up once again in Seattle. The route provided almost every type of driving condition, from remote mountain roads to traffic-packed Interstate highways. And the weather did it's part to add variety to the adventure too -- from cold rain to bright sunshine. The idea was that we would drive one set of vehicles to get an impression of any performance differences between the two set ups. And I can say without reservation that in each instance the Monroe-Walker modified units out performed the stock units by a wide margin. The ride was smoother in each case, and this writer was surprised by the higher performance on the modified units with the Walker Mega Flow RV Exhaust system. Admittedly, I'm a novice when it comes to knowing much about the automotive side of an RV, and as far as exhaust systems, I thought they were there simply to reduce the noise levels, never dreaming that these undercarriage necessities had anything to do with performance. So going in I was a little skeptical about being able to tell much difference. But I'm a believer now. The proof was in the performance. Vehicle Specifications Editors Note: Unit sets designated as "A" and "B". "A" was factory stock and "B" was modified as noted below: Motorhomes 2000 Georgie Boy Landau 33-foot' motorhome on 2000 Workhorse P30 17kGVW chassis, L29 7.4L V8. "A" - Unmodified OE product, weight 13, 460 lbs. "B" - Monroe Gas Magnum RV shocks and Walker Mega Flow RV exhaust, weight 13, 520 lbs. Truck and Pull Trailer 2000 Ford F150 4WD extended cab short bed 5.4L V8, pulling 2000 Nash 22H foot tandem axle travel trailer. "A" Unmodified OE on the truck and no shock on the trailer. "B" had Rancho RS9000's with the remote kit RS9700, DynoMax welded UltraFlo cat back dual system with side exit routing on the truck and Monroe Gas Magnum RV shocks on the trailer. Medium Truck and Fifth-Wheel Trailer Kenworth T300 converted for recreational vehicle use by Atlantic Star 8.3L ISC 275 Cummins, 6 speed Allison transmission, pulling a 1999 Teton Denver Grand 38-foot triple axle fifth wheel trailer. "A" Unmodified OE had no shock on the trailer, with a total combined weight of 34, 580 lbs. "B" had Monroe Gas Magnum RV, front and rear, Gas Magnum RV on air ride hitch and Walker Mega Flow RV all welded muffler. The trailer had Monroe Gas Magnum RV on all three axles, with a total combined weight of 34,520 lbs. continued