The Lund 1648 2010 is a flat-bottom design and the Lund 1825 Pro Guide 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.
On paper these two are close siblings in the size department - Lund 1648 2010 at 15,8 ft versus Lund 1825 Pro Guide 2008 at 18,0 ft. Weight tells a clearer story for trailering families: the Lund 1825 Pro Guide 2008 tips the scales at 1 220 lbs - 800 lbs less than the Lund 1648 2010 at 420 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 90 hp, the Lund 1825 Pro Guide 2008 has a 55-hp advantage over the Lund 1648 2010's 35-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Lund 1825 Pro Guide 2008 is rated for 5 passengers, while the Lund 1648 2010 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Lund 1825 Pro Guide 2008 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Lund 1648 2010 comes in at 12 lbs per hp versus 14 lbs per hp for the Lund 1825 Pro Guide 2008. The lower the ratio the more explosive the acceleration - meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Bottom line: Choose the Lund 1825 Pro Guide 2008 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 Lund 1648 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.