Sub overpowers everything, imo, and the drums are a bit too quiet and don't sit well with the rest of the tune, the original tune and the things you've added in don't really gel together very well. Just watch your levels and it should be pretty tight.
Structure wise I'd add something to emphasize the first or second drop, the first one comes on a bit abruptly and the second one sounds a little late, because I'm expecting something more to happen between the two of them, if you catch my drift.
My 2p.