Go to Barnes and Noble, and get a good Missouri county road map..one that shows the really great double alphabet roads. The River Rd Kamal mentioned is great...all along Illinois side. But head out to Defiance area, north toward Washington...or west of Pacific on the way to St.James, or head south into Farmington, all through the Mark Twain Forest.. just too many to name. You can go crazy with all the roads, each one better than the next.
But watch the speeds...its not just the cops, its the blind curves and 12 year old little girls around one of those blind curves on riding mower heading down the road [a road normally not attended by a heavy toed BMW owner LOL] to mow her grandma's yard. You just need one incident like that--life is over for you if not someone else. Just a thot for you to consider--our cars are fast, but thats not the point...now find those roads, and enjoy those spirited curves...there are lots of them.