I thought someone mentioned somewhere that changing the casting cost of a card in your hand was difficult / tricky due to the game's current coding.
At any rate. I like the concept, though I think the starting cost and / or increase in cost per use should probably be lowered since this is a temporary PC. As such it should probably be slightly less expensive than permanent PC such as deflag (at least for the first casting).
I can certainly see the air connection, time would also work well.