True, there are several choices for Subaru conversions but this probably has to do with all the different ways to do the conversion. With the Bostig kit parts aren't really a concern because the adapter plate that enables the zetec to mate with the stock VW tranny is the only engine part that you can't get from any ol' car parts dealer. Every other component on the engine is a stock zetec engine part (except the exhaust, but again any exhaust shop worth its salt could handle that). The other benefit is that the zetec engine is a "world car" component - meaning that Ford uses it in all of the focuses, and Ford sells the focus in every market that it is in around the world. So, in theory, if you were to convert your westy into a amphibious vehicle and circumnavigate the globe in it you would be able to find parts nearly everywhere you went. Not that you would need them - according to the Bostig website, they have been trying to destroy the engine in the test vehicle for years to no avail!

I also found on the website that only 52 kits have been sold so far, which probably explains why so few people have seen one.