BOAT Yep you will never go WOT again when you see the fuel flow go from 0.2 litre per nautical mile to over 1.5
May I ask what prop you are spinning for those speeds? I am about to invest in a 14x11 Stainless as I am not getting to full RPM any more with my 13.75x13 peeks out now at about 5100RPM.
Back on topic I also think if you go down the full on electronic path stick to one manufacturer be it Raymarine Simrad Garmin etc.. I have a mix of Raymarine, Garmin and PC (and now an iPad

) instruments and even though all the Marine stuff is all NMEA 2000 the only way I could get everything to play nice was a mix of 2000 and 0183 connections. The 2000 protocol allows manufactures to tailor their own PGN statements which don't always cross over to others nicely. Several manufacturers, including Simrad, Raymarine, Stowe, the Brunswick Corporation and Mastervolt, have their own proprietary networks that are compatible with or akin to NMEA 2000.
NMEA 2000 unlike 0183 which is plain ASCII and has been reverse engineered, 2000 is binary and is also a closed protocol although the National Marine Electronics Association divulges some information regarding the standard, it claims copyright over the standard and the contents thereof are thus not publicly available.