Personally, I like twin motors for the added maneuverability. I doo not have a Gulfstream but have been doing my research.
In the area I boat, my slip is not super wide at about 10.5 feet and my area gets decent winds almost every afternoon in the warmer months. I had boats with singles and twins and I can say that the twins are for me a necessity when docking in the wind and currents.
A single single 300 has some advantages: less weight, lower maintenance costs and simpler rigging. It is not so simple to compare the initial cost difference between a single 300 and twin 150/200s in newer hulls since it seems that new hulls only offer the digital 300 but offer a mechanical option for 150s or 200, Regardless, twins will cost more ,are more expensive a bit heavier and probably twice as expensive for maintenance. They add a bit more drag too. Based on boat test comparisons, gas usage will be about the same as twin 150s.
On the positive side the twins in addition to better maneuverability may display better low end torque and performance due to the fact that you have 8 cylinders firing (2 x 4) as opposed to 6 cylinders.
The 232 is a pretty heavy boat for its length and in an ideal world where I won the lottery, I would power it with digital F200s
232s with twins don't stay on the market for long these days. There are a lot more listings with the 300. I think that should tell you something.