So, am in the process of installing my new Hartge rear sway bar - but am unsure at to which bushings I need to use as the stock ones are a bit too thick. Any ideas? I'm sure somebody here has done this mod - Eights?

Can't help on the bushings but am curious what the thickness of the Hartge rear sway is. I'm putting Hartge front springs on and have seen the Hartge sway on ebay.de. Was wondering if it was bigger than the CSI 27mm I have. Thx.

17MM - the 27mm you list would be your front bar...
In any event, the Hartge bar is only for the earlier cars-won't fit yours - (but of course, you can use the CSI rear bar as well)

I used M3 bushings on my Hartge sway bar.