I must add that I think Bart did a good job on the porting of the module. The improvements are needed because the e-commerce was made for the 3.x ACS series and it shows, and on top of that the module as a whole is very hard-coding happy.
These 3.x- and hard-code-isms were left in the 4.x port probably due to time and bugdget constraints. We have to fix those.