The things I've learned over the years - avoid 4 point like the plaque unless it's the Schroth / BMW Quick Fit with ASM and connected to the oem pre-tensioner. 6 point with Hans preferred today based on seminars I just attended. And make sure they are new / fresh - the seminar went over the effects of UV / age on belts.

 

Ron, could you explain the 4 point comment? Especially the part about being connected to the pretensioner is good, but otherwise, bad. I'd like to know.

 

Head over to the HMS site and check out the Schroth quick fit made for BMW. It's a system that snaps into the seat belt receiver in the front and to anchor points behind. It has an Anti-Submarine design, and the pre-tensioner from the car also works with the system. So, in only that case do I understand a 4-point to be safe (see their videos). I helped BMW CCA get to the bottom of the situation - along with HMS. Some chapters had outlawed 4-points as being unsafe (which is documented), but the Quick Fit is different by design. I'm not aware of any such 4-point system that works for Porsche.