[Beaver]

On the skid plate and exhaust pipe issues, the study I mentioned in an earlier post would indicate the more that air flow is limited underneath the vehicle the less of a factor the roughness of the underside will be. In other words, if your rig has a low front spoiler, side skirts and wheel pants, the air flow (and thus turbulence) under the rig should be reduced. I also keep a record of mileage and I have noticed sustained improvements in mileage each time I added ground effects. However I did not do dedicated before-and-after tests, so I can't definitively say anything about them. The side skirts and wheel pants may have their greatest effect during cross winds, which are a component of most of the winds you'll face. Still, smoothing out the undercarriage can't be a bad thing, particularly if the skid plate is made of plastic. I don't know about your rigs, but mine is front-heavy by a couple hundred pounds. I hesitate to hang too much weight near or in front of the front axle.