Sonic Adventure 2: Battle Kart Racing Help

I played the Dreamcast one, so i assume it's the same. I just used Sonic. A good way of gaining speed is to go over a speed pad (or use your boost), then intentionally let the tyres slip. You'll stay going much faster as long as you keep the tyres slipping, so just wiggle the car when you're on straights so you don't stabilize. It's harder to control, but not too bad.. And much quicker too
He wasn't hidden on mine.. But I had got about 100 emblems by then, so maybe he's unlockable, I don't know. He seemed like the regular kind