Dem1K

iTrader: (1)

Stock piping on the CL-S....what size is it? And what size is the b-pipe if you get the Comptech? I was curious about this...also if you were to get custom piping, what size is optimal for our car?

Chopsie

Just looked on CT site, they do not give sizes.

Silverbulit40

iTrader: (2)

i believe the ct b-pipe is 2.5 in diameter.
As for the ideal size it really depends on what your plans are in the future, NA or FI

NSX-Tuner

Stock b-pipe goes from slightly less than 2 inch dia. down to 1 3/4 inch dia. after the y-split. The CT in roughly 2 1/2 dia. throughout, but narrows slight after the y-split.

Not sure about the OEM exhaust (muffler) size coming off of the b-pipe, but the CT exhaust has a matching dia. with the CT b-pipe.

Dem1K

iTrader: (1)

so upping the piping 1/2 an inch only gives us 3 whopping whp?? that's odd.

NSX-Tuner

Don't forget about improved drivability. After I got the CT b-pipe installed but before the S/C was installed, car rev'd a lot smoother through the gears and felt it had a little more torque at lower RPMs. According to CompTech, the b-pipe was built for S/C'd CLS's which benefit much more - 6 to 8 WHP gain with even better drivability.