Just got back from San Carlos, Mexico. From Albuquerque to San Carlos and back is around 1500 miles. Add day trips to the beach and Guaymas, a total of about 2000 miles.
From Albuquerque to San Carlos via Tucson, we towed a buddies pop up trailer that weighed in at about 1800 lbs, had 4 adults and all the supplies that could fit. Average speeds were about 68 mph, as my other buddy with a Nissan Titan and a 4500lb, 22' TT was having a hard time with speeds any faster. His truck has the power, but starts to require constant downshifting to maintain speed above 70 at even the slightest grades. The CRD did great, better than I expected with the load. Just set it and forget it as far as speed goes. I tried pulling away to check stability and had no problems cruising at 75 with bursts to 80. The speed would stay dead stable on all climbs dropping no more than 2 mph. The entire drive down there I was trying to figure out why Jeep doesnt offer say, a 4.2 CRD in a larger platform vehicle. Something large enough to pull a TT like above. Anyway, with crap local diesel the average mpgs were 21.5. Upon arrival in Tucson, I sourced some B20 and filled up. We also met up with another buddy also pulling a pop up. So to recap on the group, a 2005 Titan towing a 22'TT at 4500lbs, a 1986 Suburban 350 towing a 2100lb pop up, and a 2005 CRD towing a 1800 lb pop up. The gassers were literally averaging 10-11 miles
which meant stopping for fuel every 175-200 miles. From Tucson to San Carlos, about 350 miles running B20 mileage shot up to 23.5 mpgs! The CRD would hold steady as the gassers would fall far back on the climbs and catch back up on the falls.
In San Carlos on the beach I was asked to pull a couple of ppl out. With 20 psi in the tires(aired down from 45), in 4 lo, extracting those vehicle required zero throttle, literally. Just put it in gear and let the foot off the brake, and out they would come.
We met up with a buddy down there that has a Powerstroke, so I was relieved of towing duty on the way back. I also didnt wait up, as travelling at 60-70 for the next 2 days didn't appeal to me. On the way home we travelled fast, averaging 80 mph and still pulled in 26.5.
I would say the Magnaflow is worth 2 mpgs, after all these miles. It also adds some def. torque at lower rpms with less fuel.
After towing sometime, I bet this vehicle could handle 4000lbs no problem, although one would have to counteract the vehicles instability with slower speeds for safety. Very impressive little truck.
Hope this info is helpfull to someone,
Greg