Personally for pretty much anything but the drag strip I prefer a helical limited slip. I would rather not deal with the poping & chattering when going around a corner, the required special oil, and the wearing out of clutch discs.

As someone that is running the phantom grip and has run quafie's in the past I would not describe the phantom grip as horrible. Would it be my first choice? Not even close. If I have been given the option I would have purchased a Quafie for $1500 vs. $375 for the phantom grip. But given our complete lack of options the phantom grip is better than nothing. Or better than sending Kleeman ~$2600 (or whatever the price is) for pretty much exactly the same thing.