Sorry for late reply, but wasn't around for awhile. We've had a 91, 638 for 6 years now. Twin 454s. It has been a great boat for us, no structural or serious issues at all. Best cruise is about 3200 rpm yielding around 20 knots. However, we rarely run at cruise here on the Mississippi. We can almost triple the mileage by running at hull speed, (no higher than 1200 rpm). Sure it's only going about 10Kts downstream or 7Kts upstream, but it's relaxing, quiet and efficient. One area to keep an eye on are the engine hatches. In a real heavy rain mine tend to overflow and leak, spilling a bit of water on the engines. I'm talking about a couple of cups in a two hour, super heavy downpour. It has not been a serious problem for me, I just clean up asap. However, I'm planning on adding an additional drain channel under the area one of these days. Probably about a two hour fix . . . Any specific questions, please ask. Will try to check back more often . . .