Are you purchasing a new or used 2320? If new, get the 300, if used get the 250 for sure. The older 200, 225, 250's are the same block but the 250 is different than its siblings in 2 ways. First, VCT (Variable Cam Timing) second I think is the throttle body or intake. Someone else can correct me on that part. If it was me getting a 2320 then hands down I would get the 250. If your getting a new one, go for the 300. IMHO, there is nothing worse than an underpowered boat. It's not just about speed, it's also about handling loads when you have them. Good luck