The Sea Fox 180 Viper 2013 is a deep-V design and the Sea Fox 256WA 2008 is a modified-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
Size is the most obvious dividing line here. The Sea Fox 256WA 2008 measures 25,0 feet overall (2008), giving it roughly 6,9 additional feet of deck space compared to the Sea Fox 180 Viper 2013 at 18,1 feet (2013). Weight tells a clearer story for trailering families: the Sea Fox 256WA 2008 tips the scales at 4 100 lbs - 1 600 lbs less than the Sea Fox 180 Viper 2013 at 2 500 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
The power gap is worth calling out. Rated to 400 hp, the Sea Fox 256WA 2008 has a 285-hp advantage over the Sea Fox 180 Viper 2013's 115-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Sea Fox 256WA 2008 carries 150 gallons versus 40 gallons in the Sea Fox 180 Viper 2013. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Sea Fox 256WA 2008 is rated for 10 passengers, while the Sea Fox 180 Viper 2013 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Sea Fox 256WA 2008 could be the deciding factor.
Bottom line: Choose the Sea Fox 256WA 2008 if your priority is putting more people on the water - it handles 10 passengers and at 25,0 ft it has the deck room to back that rating up comfortably. The Sea Fox 180 Viper 2013 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.