Turbosmart BOV's use a different fitting to the HKS ones, so by the looks of it you will need to by their MR2 specific adaptor, and then the HKS flange adaptor on top of that.
Americanautos have a pricelist online, $80 and $39 respectively, might be better off looking for the proper HKS adaptor itself or go for another option depending on how much you think is reasonable to fit the BOV you already have.