It also depends on what part of the country you're in. Living in the NE, I couldn't see not having a 4WD truck. And while the higher rear end ratios may kill mileage, I believe they help w/ towing capacity, and overall w&t on the truck when towing.
The 4WD isn't going to do anything for you on the highway, but as Tony pointed out, it can help in the paddock. Paved paddock space is at a premium at Summit Point, and the 4WD has definately come in handy there. And if you race at Nelson Ledges...
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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608