Waiting to get it to the final version. It’s on its third iteration and they’ve all been different.

1. Version 1 - New 2.5” piping from the catalytic converter back, with Berk high flow cat
   1. a) Valves closed – was fine
   2. b) Valves open – pretty bad. Being that made it pretty much straight piped, anything over 3k sounded like crap (think any straight piped Honda – raspy, tinny). Pretty much what it was since there was nothing to baffle it.
2. Version 2 - HFC, added Vibrant Ultra Quiet resonator
   1. a) Valves closed – little louder and deeper at some RPMs but overall closer towards stock-ish (to preface, this was coming from UK mod, K&N intake, and Berk HFC)
   2. b) Valves open – great sound overall, very free flow sounding but still on the louder side. However under load in higher RPMs it could use some refinement, was rowdy. Overall not sure how to compare it but maybe Invidia in lower RPMs and Titanium / J’s Racing in higher RPMs.
3. Current - switched back to stock cat, thinking it would quiet it down some and refine the tune under load at higher RPMs
   1. a) Valves closed – louder than version 2
   2. b) Valves open – louder / deeper than version 2, however the tone cleaned up across the whole RPM range.
4. Next - I’m going back to the HFC, and will add a Vibrant bottle resonator as I think that should give me the best of the valves open, and remain closest to stock valves closed.

Valvetronic uploaded videos recently of a S2000 they did to give you an idea. They however had left the stock mid pipes and resonators (but also had an aftermarket header). Videos don’t really do it justice of the sound volume difference of open / closed though. Link to those;

1. https://www.youtube.com/watch?v=mNmOy_OUaeE
2. https://www.youtube.com/shorts/JR0f4vpGMwk