one of the pics says it's a 4 ohm model. doing a sealed box would be easy, just make it the dimensions that you want to fit to come out to 3 cubic feet. but imo i'd go ported. just cuz i personally like ported over sealed. and easier to tune lower imo. if you wanna go that route i can help with tuning
EDIT: also...according to FCsteve's post...i'd make it at LEAST 4 cubes instead of 3