Everything I've read on EQ has said that it is either worthless or only works if run for a very long time. Strength gains reported were minimal, and most likely attributed to diet and training more than the EQ. Endurance can be improved, and IMO this is the only reason why anyone would ever want to take EQ.

Improvements in vascularity can be made much more easily by either salt loading/depleting or soda loading. The problem is that you need to know how your body responds to those. You also have to accept that for the first week you will look worse than you will ultimately.

4 weeks out from a contest I'd be more concerned about diet and planning my water cut than trying to make any radical changes. 4 weeks out is really 3 if you are doing things right. You want to be in 100% contest shape 1 week prior to competition. Then you have a week to make minor tweaks if you find you need them.