The only thing you need to brush up on for 1/4 scale is battery management (high-torque servos, redundant battery systems), engine starting/tuning and car packing. They are actually (IMHO) easier to ground handle and fly once under their own power. Getting them to and from the field is the real challenge, and keeping them at home is VERY space consuming. Measure your car first. As with any scale, some designs are handfulls, others are tame.

The Cessna 188 Ag-Wagon was recently a very popular choice for a kit. It's all about low & slow manouverability. Kyosho offered one ARF, several places offer patterns (I thing Don Smith did or does)

Another full-size duster choice was the Pawnee D PA25-235, also used as a glider tow.