For waja cps, grounding is so important as stock ground is insufficient for it. Only two point needed in waja cps. Compressor and also alternator. For VS, I also dunno. People claimed so many improvement while I test it 1 by 1, i dun feel any different. Only I guess is, buyer pay that amount so they mentally think it improve.

Finally I done all my sealant project. Pump in sealant in all welding point chasis. I realize it have alot big huge gap between the welding point which cause chasis sound. Bought 4 bottle sealant which use to windscreen, then pump in all removing all the body out. Now it have no more chasis sound and feel abit solid.      Leaned this from 1 ah pek which pro in catching chasis sound and see him done on alot car especially after accident repair car.