While the OP is harsh with his criticism, he has a very valid point. The software updater is considered by me, in my opinion, a PUP. A new, non-standard module like this should have been an opt-in install, not an auto-in install via the avast! update feature (7.xxxx to 8.xxxx).
avast! should have somehow made the update much like a brand new install with the opportunity to chose what modules were going to be installed, rather then installing a PUP automatically and worse yet, silently..............This is what avast! is supposed to protect the end user from in the first place.