Lived there till i was 21. My family actually still live there. I know Cape Town back to front.
And yes. The parties in Cape Town are insane. 10x better than any parties ive been to over here in London.
You'll need to ask around about Vortex, or even better Alien Safari parties. They are generally all outdoor. Only in winter its indoor. Vortex has the biggest fuck-off sound rig ever, so i would recommend that just so you can hear it.
There are parties every single weekend, (and sometimes during the week as well), You can find flyers, tickets etc from a shop called "Space Station" in many of the malls in cape town ("Century city is the biggest shopping centre in cape town, I know there is a Space Station there.)
Hope that helps.
PM me if you need any more info, i could probably organise you some weed too.