im going to treat my my95 wrx to a decat downpipe on pay day as the pre95 are mot friendly decatted, but im abit unsure on what size or brand to go for scoobyworld do the afterburner 3'' narrowing to 2.5 or a 3'' tornado from scoobyparts which has the 2.5 convertor gasket? im im currently running a tsl group n back box & straight through middle section