The three main things are (1) portamento (its the pitch movement that mostly gives it the tearing sound), (2) distortion of the signal - however you go about that, but any waveshaping can potentially get you the characteristic you're seeking... Bitcrushers, granularizers, etc.. that's what gives it the raw hardstyle edge effect.. Use that to ride the fine line between noise and tone. (3) reverb reverb reverb.
I just got Z3TA 2, which improves upon the original but was always known for it's wave-mangling capabilities (see #2 above), and I only started playing around with it because I've been spending a lot of time learning Logic on the Mac (and Z3TA is PC only like a lot of good synths), but it seems to be perfect for this category of sounds (any type of trance sound really), because of how easily it lets you distort the oscillators in all kinds of creative ways.
http://www.cakewalk.com/Products/Z3TA/