This is really good!
Not really my type of stuff. A little too poppy/clubby, and I'm not sure it's dubstep, but it seems you took time to pan, mix, etc. Could use maybe some side-chaining to make everything pop a bit more.
I don't really like that duck-y lead around G3-Bb3-F3 you use as a fill. It just doesn't fit to me. Lead also is bland to me, period. Keep trying though. You'll get there.
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