just did a try of a Sandburgen dubstep collab myyself ... I'm not a huge fan but I've heard some really good track and Dj Sets ... I like good music !!! (except fantasy metal)
ya i agree about the drums the main bass/beats/drums should be balanced. its kinda a trip that like all the bass kick is on the right. other than that this is great. i like it
The only thing I would change would be to bring the main kick to the middle instead of having it panned to the left. In general, in exception of hi hats, you should always keep your drums centered stereo wise. Just some advice