You have a couple of different options here. First of all, per the brochure your hull is rated for a maximum of 450 hp, of which if you wanted to maximize your horsepower levels while also keeping the weight as low as possible... your best bet imo would be a pair of Mercury 225 FourStroke series outboards at 475 lbs a piece. Which are actually lighter than what your claim is for the current ox66's on your boat, and I'd get their digital or fly by wire versions of those motors. If on the other hand you aren't looking for maximum horsepower, you could either do the 200 Mercury's as well, or another great option would be a set of Suzuki DF200AP's. Those weigh in at 531 lbs a piece, which are essentially the exact same weight as the Yamaha F200's you mention above, on top of which the Suzuki DF200AP's also come with their digital/fly by wire controls, which I'd take over the mechanical ones. Both Mercury and Suzuki are going to come with a standard 5 year warranty vs Yamaha which comes with a standard 3 year warranty. I'm sure you could always pay more for a longer warranty, but I imagine twin Yamaha F200's are going to probably be $5k+ more than both Mercury and Suzuki, and that's likely going to be for the mechanical models. There are a few guys on here that have 265 Express's or a 270 Islander that have twin Suzuki 200's on their boats and they have good things to say about them. I imagine you'd likely be just as happy with them on your boat as well. In fact, I even just checked the Yamaha website and a single F225 is $26,470 vs the Suzuki DF200AP which you can find online for just over $15k. Even the Yamaha F200 with digital controls is going to be almost $26k for that as well.