Please can some one explain the differences between the various common Weber carbs that I'm looking at using on my zetec. These mostly include

IDA down draught
IDF down draught

DCNF down draught

DCOE side draught

I'm not really sure what to go with. The DCNF and DCOE stuff is a lot dearer to get hold of than the IDA/IDF stuff, so I'm assuming these are the performance based carbs.

Also, if anyone can shed any light on the DGV 32/36 stuff and whether it's any good that would be cool too.

Thanks a lot

Dave