It always appeared quite utopic, despite the claims that the original poster made, i.e. this being proven technology that industrial and heavy duty diesels manufacturers (even north american car manufacturers) have used it at times etc. etc.
I have just received a new Summit Racing catalogue (I once ordered a steering wheel from these guys, and since, they send me regular "phonebook" sized catalogues...) while just casually browsing through the latest catalogue, I came across the following page:

Here they mention the benefits for Water/Methanol injection for general, everyday diesels in the most common North American Pick-Ups (Dodge, Ford, GMC) and offer a variety of complete systems.
Now, of course, we are talking about large displacement engines with 5, 6, even 7 liters of engine size and our meager 2.5's and 2.8's appear particularly weak-breasted in comparison... also I don't think that a 2.5 4 Cyl diesel would be too happy receiving a shower of water and methanol designed for a V8 or V10 engine three times its size...
In any case, I wonder if anybody on this forum has ever experimented with water/alcohol injection and if anybody knows of systems that are better suited to spray that stuff into a small 4 cylinder diesel.... Just trying to find some information... at this point I have neither, the disposable cash for such a system, nor the time to fiddle around with such stuff nor do I want to run the risk of damaging my Delica's powerplant... but I nevertheless find it quite intriguing and if they offer that stuff for widely available North American Diesel Pick-Ups, maybe it's not the last thing for a Delica either?
Cheers,
Chris