Lets see if I can help you with this WIP with my opinions<------ key word there.
First thing, the 'melody' synth from 0:43-1:17 and then from 1:55-2:33 might need a serious tweak or be completely changed out for something less intrusive. It doesn't flow with the rest of the song at all and it just overpowers everything else in the song.
The bass you used from 0:43 on needs to be louder and deeper unless you were using it as a background melody/effect in which case, add some deep bass. Also, the hi hat is loud, and the pattern needs to be changed. The 1/8 note thing is good for techno but it kills in dubstep. I suggest adding 2 more hi hats to the kit (different ones) and making the hi hat line more of an effect used to aid the drums in sounding more full/complete.
Add some effects into the song (other than the female laugh and moans) You did a good job with this after 1:30 then you stopped adding tactical effects/sounds/synth fx and I think it's because of your melody synth. I know I keep coming back to that, but there's something about it that I just don't like. I think because it's too straight forward. It's all 1/8 notes for a bit then 1/4 notes and it makes it very boring. Try playing with it a bit, take some 1/8 notes out and drop in some 1/16 notes and see how it sounds (but don't get too crazy with it)
I know I'm going all out of order here, but the intro needs some help too. I think the piano needs to come down (volume wise) a bit because it clashes with your deep kick and bass line.
I know that dubstep is supposed to be filthy, but it's tactically placed filth. You've got a great start to a song and I hope you'll finish it!
Keep it up!
TorkKey - feel free to check out my new song ">TK< OMG (complete)" and give me your critiques.
Also if you're using reason, lower the sample rate down to about 2,000. That SHOULD help reduce that distortion given off by all the synths/effects taking place at one time.