Is this class overpowered, broken, or fair?

[sadi]

Think of it as a double barrel shotgun, he can hold 2x his con in spell levels, fire off his con in d6 twice per round. Then probably sit there with a ready action to absorb spells, since it'll take him quite a few rounds of sucking on wands to refill. The most you can hold is 8x your con although x5 or x6 is probably all he could get away with without having to worry about failing a con check.

The overcharge if I'm reading correctly means if he had a 25 con, he could hold 150 spell levels fairly easy, do 2 range touch attacks at 75d6 each, and then have to come up with something else assuming that his 2 75d6 shots didn't obliterate whatever was sitting there. Yeah it sucks that he just spent 2250 in gp to drain 3 wands to charge up, but it's probably worth it to him just to be able to roll that many dice at once.

[Doc Roc]

Getting those spell levels will be virtually impossible. You'd need to pay me to play this trainwreck of a class.

[Edea]

I...think I would rather nudge him in the direction of either the Spellthief class, or just towards the general 'Gish' builds and PrCs (Paladin/(Sorcerer or Bard), Warblade/Wizard, Jade Phoenix Mage, Abjurant Champion, etc.). The Spellfire Warrior isn't really necessary.