My 550 rides and drives surprisingly well. Very smooth. But it has a heavy steel flatbed on it with boxes full of tools. The truck is 12,500 lbs without fuel in the slip tank. It would be worth asking@f1hdr how his 450 pickup road empty before he converted it to the service body. The main thing for daily driving is the rear end gearing. I think the 450 pickups come standard with 4:30 gears. I'm not sure if the new alumaduties offer other options...? My 550 has 4:88's, which is perfect for heavy towing, but definitely too low for dd use. I plan to add a Gear Vendors overdrive to my 550 for driving empty which will give me the equivalent of 3:73. That will greatly improve milage and extend motor life when running empty.