If you've come from an MBX5 then you will have to alter your driving a great deal in order to make it work, the MBX5 was a car that was very forgiving to drive and you could get away with so much more. The Losi needs to be driven with more finesse and more delicately, you need to be smooth into and out of the corners, hit the apex's right and the speed will be there in buckets. Just try and drive it as slow as you can and work on the pace from there, providing you keep it on its wheels you'll be suprised just how quickly you can go with it driving it so slowly.
I would have to agree with everyone else though, it takes a few meetings to fully bed in, after a few meetings it'll loosen up and become more forgiving to drive.