OK VW is still getting even with me for taking them.  A couple 
comments to qualify my previous ones, Dansk exchanger are no where 
near as well stamped.  If you look at a german set of the '76-'78 
style the oval output tubes are beautiful clean, regular shaped.  The 
dansk are crinkled and ugly and hard to fit.  Funny thing is I think 
it may be because the Dansk seem to use THICKER steel for the box, 
the lighter weight comes from less aluminum exchanger inside not the 
outside I think.  But the main annoyance is towards the front, the 
lip that meets with the blower is nowhere near correct, just enough 
to be miserable,  the upper lip is cut a bit to far back, the holes 
on mine misdrilled slightly, and the upper lip is slightly to high.  
All these slightly's about 1/16" each but they stack up to give you 
headaches.  AND the oil filter problem is correct.  Depends of course 
on how bowed your U tubes are and how the box you get is made but 
with a Bosch filter the  box touched mine.  The problem is obvious, 
another cheapo maldesign.  The German box side seams are rolled 
together and crimped close to the box (stick out no more than 3/16") 
the Dansk is simply spot welded and cut roughly about 1/2" out, so 
that eats up all the room at the filter location.  I ground 1/4" off 
mine there and still can only fit a thin stamped steel wrench not one 
of the aluminum style.  A final quible no drain holes drilled I did 
it myself in the stock location and one other.  Actually though the 
fit with the muffler was OK and once everything was massaged and 
muscled into shape it all worked out fairly nicely.  The flapper 
valves are as nice as stock, the bellows are quite nice fit great, 
and the silicone seals are actually a miracle in themselves for ease 
of installing the bellows compared to the old asbestos units.  A 70mm 
hose clamp will just fit the connections if you preinstall it on the 
bellows with the silicone seal then muscle it in.  And one more 
gripe, no bolts and no little cable connection toggle thingy for the 
heater control cable lever.  Better hope your old come apart OK.
I feel that on the vanagon and on a '73-'75 or '79 with the round 
output holes these problems would not be so bad, it is getting the 
oval to fit correctly.  In fact a Vanagon would be a breeze with no 
fan housing connections, course on all those you risk head stud 
problems instead.

John
vwbus@netbiz.net