What is the BO? And what is the general strategy against maxim spam?
There's not really much of a build order... I mean I don't really play to a list.
Generally I like an early kubel and a couple of volks. And I really like getting a flaktrack.
As for strategy, it's all about being aggressive and keeping him on the defensive. Coming at him from every angle, setting up multiple fronts of engagement. For example late in that game I am harassing his t3 building with a puma and when he moves his AT guns to position to defend he runs smack into two squads of infantry which really hurts his efforts. If he garrisons, just ignore that area of the map and go push somewhere else.
You have to use your flaktrack cautiously though. This game shows what happens when you use it recklessly, and then I redeem myself by building a second one and using it much better utilizing line of sight and shot blockers to ambush squads, or maneuvering it so it can still harass without being vulnerable.
The units you build aren't super important, it's really a matter of using them effectively.