Both the Monterey 340SY 2009 and the Monterey 400SY 2009 are modified-V designs, both built in fibreglass, so the buying decision usually comes down to a handful of practical questions: how many people are you putting on the water, how far do you trailer, and what does your tow vehicle weigh?

Size is the most obvious dividing line here. The Monterey 400SY 2009 measures 41,0 feet overall (2009), giving it roughly 6,0 additional feet of deck space compared to the Monterey 340SY 2009 at 35,0 feet (2009). Weight tells a clearer story for trailering families: the Monterey 400SY 2009 tips the scales at 22 000 lbs - 7 800 lbs less than the Monterey 340SY 2009 at 14 200 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 435 hp, the Monterey 400SY 2009 has a 60-hp advantage over the Monterey 340SY 2009's 375-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Monterey 400SY 2009 carries 330 gallons versus 210 gallons in the Monterey 340SY 2009. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.