NOT an expert here! But what would be the harm to fire up MAS without CRM installed? If it works great, if not, you still have another day of your weekend left to get it installed.......................
In a way, isn't v4.5 just a dfferent flavor of EES? Only one of my v4.5 installs is using CRM and the ones without run without a hitch. Just don't activate the CRM module in MAS.