I thought I'd post a link to 4 gear gear boxes for the atomic carbon CR2 or any other mid motor losi. The quality of them is amazing and you will not be disappointed. He makes them in batchs so when there's non left in his store, check back often until more are available. Best of all they're only about 35 pounds shipped.
http://cgi.ebay.com/PSI-Racing-4-gea...item4cf26ca9a2