The effect is made by using a very high sample rate, so that even when slowed down, the material will still retain a lot of high-frequencies, as per Nyquist blahblah, etc.

Render the bit you want to slow down, and do it in the highest possible setting (I found that 192k worked well,hehe)
Open it up in your wave editor. I use soundforge, and it has a function called resample. Set the sample rate to the original sample rate of the track, in my case 44.1. and then check the "set sample rate only. Do not resample"-box. This way the file will be interpreted as 44.1, and thus slowed way down.
BUT since it's been recorded at 192k, it still has a huge amount of high-end sound in there from my synths and digital drum machines and whatnot.
This way your "drop everything an octave and play it at half speed" breaks won't sound like that's what you're doing
