Help Repowering Boat

[HookedOnMarsh]

Hello. I'm looking for any input about replacing my old 86 175Blackmax on my cuddy cabin. I'm looking for a used motor in the 150-200hp range.

If I stay with Mercury, will all my controls and gauges work with say a 2000 year model or newer?

Any of the EFI or DFI motors I should avoid?

What kind of gas mileage increase will I get with these newer motors? And which would be better 150 or 200hp on gas mileage and performance?
This boat will be used to go offshore with a full load of 60 gallons fuel, ice chests, and kids.
Thanks for any advice.