Last time I did one, I mailed it in around November, check came middle of April. They seem to be reliable, but you will forget it exists before you ever get the check.
2012 Kia Forte EX 2.0 I4 6AT 30k- PP 5w20
1994 BMW 530i, 5MT 193k PP Euro 5w40
2009 Honda Accord 2.4 I4, 5AT, 159k- M1 EP 0w20