Leman Russ Demolisher

Its a Demolisher for now, but it is destined to become an executioner. With the coming of the new codex and the lumbering behemoth and squadron rules, I just can't get the executioner out my lists. The ability to drop 5 plasma blasts a turn has the potential to ruin any armies day. Whats more, I am seriously thinking about taking two squadrons of two tanks, both centered around an executioner. Is that too dirty for a tournament list?

I will order the plasma cannon turret(s) from forgeworld soon. I am torn between the two and can't decide which one I like better: