ok this may not be a problem at all, then again it might be.

just received a new tanabe hyper spec exhaust, tanabe said piping is 60mm, which should be just fine for ITR motor.
problem is: inside the resonator and muffler piping is @50mm!!
beyond that the resonator is full of big *** louvers which close that clear flow space down to 1.5" or so!

has anyone found this type exhaust (5zigen fireball for civic does this too) format to rob power?

thanks.
-steve