I run a 3" 5-point harness in my 80 911SC.. have a nice Recaro driver seat that has the opening to properly route the shoulder straps through the seat. One thing going to a harness system - it's not a quick jump in the car and go... it takes some time to properly strap in - and once you are nice and firm - actuating any heater controls - radio - instrument panel - you have to loosen the straps ..