I have Fast Intentions HFCs for sale, located in the bay area (south bay). They were on my 350Z when I bought it back in 2011 (Z had ~26k miles, HFCs had ~10k miles on them) and sounded really sweet. Swapped to stock with the intention of putting them back on, but never got around to it. Asking $500 obo, so shoot me an offer. Probably will put back on eventually, if no interest.

"Here's some additional info:

Finish: Non-Polished Stainless
Original Cost: $640.00

Designed to be an addition to your cat back exhaust system. Our high flow cats eliminate your stock catalytic converters and free up back pressure. This is achieved because we increase the tubing diameter and use a less restrictive catalytic converter. By doing this, you free up torque and power throughout the entire RPM band. Your overall sound volume will increase while making your exhaust note deeper and smoother.

PRODUCT INFO:
2.5" T-304 stainless steel tubing.
The catalytic converter is a 300 cell metallic core in cased within a spun stainless steel shell.
(Standard) J-Bend style O2 sensor anti fouler to ensure the CEL light STAYS OFF.

All gaskets and hardware are included.
Limited lifetime warranty on all welds and craftsmanship.
Made in the USA

BENEFITS:
An increased average of nearly 18 RWH and over 20 FT LBS of torque in conjunction with our cat back exhaust system.
Refining the stock note by increasing the depth and volume.
Absolutely NO RASP from RPM idle to RPM redline in conjunction with our cat back exhaust system.
They bolt in to the stock location with no cutting or welding required.
By our high flow cats being MUCH less restrictive than stock, you will reduce your EGT's (Exhaust Gas Temperatures).
Our high flow cats weigh 13 LBS = 9 LBS lighter than the stock catalytic converters."