The HPMX are chinese weber IDF clones of unknown quality,webers used to be italian made there the best but are only available 2nd hand,then the webers were made in spain for a while quality went down a bit and now there made in the US of A again unknown quality.But if i had to buy a set of carbs for a twinport 1600 ide get a MATCHED pair of Dellorto 36 DRLAs or a MATCHED pair of Weber 40 IDFs,and ide buy them of ebay in the US off a guy called, alfa1750,hes based in italy and only sells italian carbs and he'll set you up with the venturis of your choice.He sells carbs only yule then need manifolds linkage and filters,good luck in your endeavors,Mick.
Or you could buy these Chinese clones
http://www.thesamba.com/vw/classifieds/detail.php?id=327652 :P
[ Edited on 21-9-2006 by lugnuts ]
Dont listen to what they say,just watch what they do.Oh yeah ive NEVER finished anything ive started.:o