The new Crew Cab is a smaller inside than the Mega, but bigger than our current crew cab model (I've sat all three configurations). In the Mega I can have the driver seat all the way back, and my knees do not touch the back of the seat. In the new crew, my knees do touch the seat. In the current crew (3rd Generation) I barely fit in the back seat. Granted, I'm 6'9" so I'm not the normal model for back seats, but the Mega is the biggest.From what I have read the only difference between the all new CrewCab and the mega cab is behind the rear seat storage.