Eric, first off welcome to the forum. the Volvo EFI system will be very hard to find here. there is only a hand full of people on the site that have them. personally i think that and the DPX drive are one of the best drive systems ever engineered but unfortunately our market is dominated by another entity and they never sold very well. what part of the world are you in? i race an Ocke Manerfeldt/Reindl batboat in OneDesign with the 320DPXi setup.
one other thing, i believe the DPXi drive has been discontinued by Volvo but im not sure about replacement parts. good luck.