My advice is to drive the RX-8. Why do you need two cars? Theres nothing that says you can't drive the RX-8 year round. You might say well the winter weather and miles will decrease its value. My take is that statement is shenanigans. The car has no value if you dont drive it, its just an expensive lawn ornament. You probably bought it because its a driver's car, so get out there an drive it. Don't worry about snow, DC doesn't really get any and if youre really worried get a new set of wheels with some winter tires and you'll be off to the races.
I've got a 2001 Camaro SS that I drove this winter in CT where we had a pretty solid snow season including a day with 25"+. While I wouldn't have gotten anywhere that day, other times when there was 3-6" on the roads, it drove fine. Just takes a little finesse.
Either get the matrix and ditch both other cars if you want to drive an appliance, or if you want to have that real car, get rid of the ranger and drive the fun car.