One thing to say - Heatran Lv.X in a Magnezone deck is just stupid. Actually some of the most terrible things you can play in this deck. You don't get any benefit from its body, and the power is only useful if you attack with Magnezone Lv.X, which is not your mainhitter (this was already mentioned). Since you can recover energy easily with Super Connectivity, you don't need Heatran. It isn't even able to recover special metal energy, unlike Magnezone SF.
Can't understand how people talk about lack of bench spaces and want to play Heatran at the same time. Aside from the bench factor, it's a basic Lv.X, that means you can get other useful Pokémon with same effort. While even stuff with no synergy like Cresselia Lv.X would still be a lot better than Heatran in Magnezone, we have a a really good tech here - Palkia Lv.X.
Let's just compare.
Palkia Lv.X does nothing while you don't have at least Magnezone DP in play. With Magnezone DP
and Magnezone Lv.X you can use its power without any drawback. That's a Gust of Wind every turn!
Heatran Lv.X does nothing while you don't have Magnezone Lv.X in play, therefor you need another Magnezone below it. Conditions to use it are almost the same, while it's effect is pretty low. You can recover two energy in case you attack with Magnezone Lv.X. But do you really need that energy with the powers of Magnezone SF
and Magnezone Lv.X? My expeciences with Magnezone have shown that you don't get energy problems once you are set up.
So I hope nobody will talk about Heatran in Magnezone any more.