In my 1997 330DA the port tank is listed as 112 gal and the stbd tank as 108 gal per the parts list. The spec sheet shows a fuel capacity as 225 gallons so take your pick. I'd be inclined to believe the parts list.
It probably depends on what you have to begin with. I am installing Fox Marine Gateways that will transmit all engine data to my Garmin displays. The hardware to get from the engines to the display was about $700.
"Dinghy Caddy" is another system that is a little different but looks to be a viable option. Also, a guy here in SE Michigan is making a set similar to the basic Hurley for a good price. Search "dinghy davit" on ebay. The guy is from Clinton Twp.,...
