I think what the OP is asking is:
"When a tune, like the Cobb Agressive Map, SPECIFIES an upgraded Cat-Back Exhaust as a requirement, does the BMWP Exhaust qualify?"
He wasn't asking if its a good upgrade or if it adds any power... He was asking if he can use the Cobb Agressive Map with the BMWP Exhaust...
Unfortunately I don't know the answer, but at least I read the question...