We have a Ford Racing 4.56 gear on the site, but it's a bit more expensive than the Motives. I know Motive does make a 4.56, I will check on pricing and availability in the morning.
To anyone else viewing, Motive does offer a 4.56 get set in Street Performance and High Performance versions. They are $174.95 and $199.00, respectively. I also have them in stock and ready to ship.