Originally Posted by Daddy-O
Definitely have them check and align. (Don't forget the rear may be out from the factory too. My Scion xA was out 2 degrees and the dealer had to shim one rear side. Rare, but it should be considered when they check alignment.)
Your Scion had a semi-independent rear, the Rio is solid rear axle, so won't need a rear alignment. If, and it's pretty extreme, the rear wheels aren't lined up with the front wheels in the Rio, it'd be down to a structural fault which isn't good, but in that case it'd only 'crab' or steer to one particular side on the freeway. OP says it goes right or left.
OP: check your wheel nuts are on properly too.