Re: switching outboards and gauges
Not really.
Gauges are gauges so I'm guessing your changing them because you like the style of one over the other. That's pretty straight forward.
You may need different cables for your throttle and shift if you have a universal control or your going to need to swap the control boxes (might still need cables due to length they are not expensive).
You might need a different end for your fuel line.
Shouldn't be to much hassle.