This only really applies to me. Guys with E36's with E36 engines or E46's with E46 engines, etc, can buy a once off Remus unit like yours, and know that it'll fit because it was made for them, and have correct power gain figures. Me, I have an E36 engine in an E30, so the fitment has to be custom, and since the performance figures these guys quote is for their complete system, I shop for how it sounds, and will get proper headers/piping made up, and hope to get a performance gain somewhere in the system. That's why I was asking for Stromung boxes, they sound hot, don't know their performance gain by themselves, and no one can really claim one for standalone boxes.