Paul raced at both the Cactus Classic and the Losi race in Florida with his XXX-4. At the Cactus he was 5th in the B -- highest finishing non-factory driver. At the Losi race he was 2nd in Sportsman 4WD mod.
The Durango is a fabulous car -- fast and nimble. We've only seen it with capable factory drivers, but they make it look very good indeed. They are right with the Losis on the straights and handle the bumps & jumps better.
XXX-4 has 2 problems:
1) Too heavy. Nothing else to say about it. Too heavy.
2) Chassis is too low. The large 41-tooth diff gears mean that the chassis must be closer to the ground. The center point of the diff must be about level with the center point of the wheel (bones level), so a bigger diff gear means the chassis MUST be lower. When going through a rough section (think moonpies) the chassis hits the ground and throws the car off line. You absolutely MUST backside all jumps -- if you land even slightly long, there's the chassis on the ground again, and the car's off-line.
Result: you have to drive it PERFECTLY or else. Paul and I are coming to believe that the XX-4 may be equally as fast -- what it gives up in straight-line speed it makes up in handling and driveability. One thing for sure: in both of the latest "big" races, a well-driven Durango has won against the best Losi drivers.
Engineering Without Fear