just curious. i installed the Borla onto my HKS downpipe but since the borla has a donut flange and changes from 3" to 2.5" where it meet the HKS's 3" flat flange, would this hurt performance much? a friend told me that if there is a 2.5" kink anywhere, its basically a 2.5" exhaust system. There are no leaks in the system and the car runs well.... but i cant really remember what it felt like when i had my HKS exhaust.

2002 wrx sedan
mods....
AP stage 2
up pipe
down pipe
Borla Hush
K&N filter

thanks
eric