Most people go with Karboy because they are similar in shape and design as the stock. They are known to be the quietest of all endlinks and have the lowest fail rate. Again I run the Whiteline links with a Hothckis bar, no issues. But like you said I wouldnt run whiteline with perrin links or vice versa. But also like Justin (brfatal) said, I wouldnt run Perrin anything (had some crappy parts from them and no customer help or support what so ever from them). But thats personal.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX