that statement might be true if everything was exact. I have several 200hp engines and just by eye sight they are that 200hp, however the engines run at 6500rpm all the way to 10,500rpm and compression is different making them different in terms of how much horsepower is actually produced. Unfortunately at some point we will have to switch to a 4-stroke engine
If both engines made 200 peak horsepower on a dyno the “overall “ performance on his boat would be similar. The 6500 rpm motor would have more torque thru the lower rpm range allowing for a higher pitched prop. The engine making 200hp at 10,500 rpms would have less torque in the lower rpms requiring a lower pitch prop to get the boat going. The end result may not be exactly the same but it’s going to be to close for the average guy to spend 25k plus thinking you are going to have any performance gains.
I know some of the newer motors may have the advantages of being quieter, more fuel efficient, cleaner etc. unfortunately usually at more weight and very costly on the wallet. If I were in the original posters shoes and was considering a repower, I think I would look into what the member PKSTV has been doing on here.
Brand new 225 promax power head with vst delete and a few other tricks. I really like what he’s doing to keep those 2.5’s alive. That setup is hard to beat on a 2003 or 2002