The Custom Weld Sport - 16 ft. 2006 vs Custom Weld Viper II Inboard - 19 ft. 2009 comparison sits squarely in the category of decisions where specs alone won't tell the whole story: intended use, storage, and long-term ownership costs all factor in.
On paper these two are close siblings in the size department - Custom Weld Sport - 16 ft. 2006 at 16,0 ft versus Custom Weld Viper II Inboard - 19 ft. 2009 at 18,0 ft. Weight tells a clearer story for trailering families: the Custom Weld Viper II Inboard - 19 ft. 2009 tips the scales at 2 400 lbs - 1 400 lbs less than the Custom Weld Sport - 16 ft. 2006 at 1 000 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.
For family outings this is probably the sharpest distinction between the two. The Custom Weld Viper II Inboard - 19 ft. 2009 is rated for 5 passengers, while the Custom Weld Sport - 16 ft. 2006 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Custom Weld Viper II Inboard - 19 ft. 2009 could be the deciding factor.
Bottom line: Choose the Custom Weld Viper II Inboard - 19 ft. 2009 if your priority is putting more people on the water - it handles 5 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Custom Weld Sport - 16 ft. 2006 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.