When two boats share the same hull type — in this case both the Monterey 243 EX 2008 and the Monterey 400SY 2008 are modified vee designs with fiberglass construction — 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?

The power gap is worth calling out. Rated to 375 hp, the Monterey 400SY 2008 has a 55-hp advantage over the Monterey 243 EX 2008's 320-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 243 EX 2008 carries 57 gallons versus 33 gallons in the Monterey 400SY 2008. 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 Monterey 400SY 2008 is rated for 12 passengers, while the Monterey 243 EX 2008 caps at 7. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Monterey 400SY 2008 could be the deciding factor.