Incredible speed; I was watching the ST version a few days ago which is far choppier by comparison. Playing your vid at .5 was more like a playable speed and even then the vid was still pretty smooth, hopefully the real thing would be even smoother – which is just awesome.
Obviously the key to a smooth game is a high frame rate + low(ish) pixel increments. I guess a lot of how smooth this turns out will be down to how much of an update the ST version does to achieve the illusion of speed – unless you can change that? I don't think it will be a problem though as it seems to me the ST version wasn't so bad already, and at least doubling it surely wouldn't hurt
I think that the ST title screen looks more like on old 60's dirt bike, and that goes for the game sprites also. Maybe the gfx artist had some nostalgia for old bikes. You wouldn't get so much 'air' on the jumps with those =)