I'm hoping they actually tested that 250mph+...I'm no expert but that car looks bit too light and short to do that speed...can't see how it will stick to the road...unlessssss...they want it to fly away :)
Mostly, you want to generate a load of lift downwards to keep the thing attached to the ground.
But to answer your question, if you define "enough" as "enough to make it go airborne", then yes. You would then have to be very careful to make sure it is actually stable in the air, or the results could be very non-pretty. And then you also have the problem of keeping it going fast in the air, when previously your only forwards force was provided by the wheel contact with the ground.
