Firstly, I'd check the actual TRO before assuming that Sarna is right. It probably is(just about every vee in that TRO got the hitch), but don't assume so.
Looking at the actual combo...not bad. You slow down, but not enough that your TMM drops. In AS tractors don't block the firing arcs of trailers(and vice versa), so it's alloys all around firepower, with the benefit of being split into two different to-hit rolls and damage chunks. I especially like the idea of being able to drop the trailer if I choose in order to provide area denial while the tank moves off to fight elsewhere. On the downside, neither unit is exceptionally durable, so the combo can be negated by destroying one or the other unit. Also, the trailer being wheeled does limit this pair from entering certain terrain that the tank could enter alone.
I like the idea, it's solid, but I wouldn't call it powergaming or munchkinism. For one thing, I think a hardcore min-max player would see 40 points'worth of combat unit that runs into real trouble after only taking for damage, and would probably turn instead to a single unit with seven armor on one card.
