The X1 uses 6 wheels, 2 secretly hidden beneath the middle of the car. You won't notice them because they are so good hidden. They say, you can see scratches on the X1 of something what has ever been a roof, pointing out the X1 hasn't always been a cabriolet. If you zoom in on the rear, exactly 8,912 mm right and left from the centre, you see another two little wheels, it's the wheelie bar.
The X2010 is the more perfectionised X1, the two wheels are lost because it didn't work as the Red Bull people hoped so. The wheelie bar is also lost and the X2010 wasn't even made with roof, to provide the roof from falling off again.
Okay, back to serious: there is no difference. The X1 is the X2010, but then from before patch 1.05. The X2010 is the X1 from patch 1.05 and after that.