Currently I have a Greddy FMIC and Greddy piping with a Greddy Type S BOV. it's on a 98 GS-T. I've been hearing that each company's BOV's are only bolt on to the same company's piping. If you are going to mix and match piping to BOV then you must weld the flange on. I really want the HKS BOV but don't want to weld unless I have to. But I guess there is no way around this.