Whoa, all these are good suggestions, I'll test diminum's suggestion (Talonflame), Mistaken's (Spikes Skarmory, MG Clefable, Keldeo and Tankchomp) and Sablenite's (Mandibuzz + Chansey, but should I take Heatran or Talonflame?)
Personally, I'd keep Unaware's Clefable to stop M-Charizard X...