Don't do the LFO lowpass stuff inside massive, instead do some slower wavetable LFO and slower (like 2/1) LFO filtering, but nothing that will limit the sound. think double notch filters, band rejects, anything that isnt highpass bandpass or lowpass. Go easy on the distortion and waveshaping options inside massive. I usually just use dimension expander and maybe some LIGHT mono flanger. If you're going to use the waveshapers, be very careful not to distort it too much or you wind up with this ungodly mess:
And remember to turn up the voice count inside massive too.
Download WOW filter and ohmicide, both great tools. Use ableton's saturator, vocoder (set to modulator so you can formant shift) chorus/flange, whatever. Get to work resampling. I would post a zippyshare of all the steps it took to make the bass in my sig, but im in ontario and my desktop is in vancouver.
Resampling is pretty much this: add a small amount of FX, bounce to audio, save. Add a little more FX, bounce, save. rinse repeat until you have a small army of shit you can assemble a bassline from. Whatever you do, for the love of god, don't just slap an LFO on the lowpass in massive and automate the LFO rate and leave it at that, please. There is so much crappy dubstep out there now it causes me physical pain. It might seem like its hard, but this is how datsik and excision and downlink and all the other big dubstep names get their epic bass.
And remember, in ableton you can always slice to drum rack, and rearrange. And change pitch indefinitely.