Found the Ribstuff site recently, and have it bookmarked as they appear to have some good deals in place.
Unfortunately it will be towards the end of this year before I can contemplate it.
With regard to the HPDIs, I've done some trawling about, and The Hull Truth (thanks dubrus) appears to confirm what I've now found elsewhere, in that the 150 and 200 appear to be as reliable as anything else, but anything over 200HP deserves the bad reputation.
The article I was reading did I believe relate to 225HP and 250HP engines, so it makes sense now.
RIBBED For extra pleasure.
Member of the ebay Blue RIB cover club.
Member of the Bombard 380 Aerotec club