Off topic, but i see your from snoqualmie Nikon! I just moved from Everett few months ago, i used to ride stevens, baker, and snoqualmie! Anyways your picture reminds me of all the trees! we don't have them down here in Texas : (

That's exactly why the hiss is louder with test pipes. The lower the cell count the louder the hiss. This is why the test pipes have the loudest hiss.

Dont forget you can get the resonated HFCs from FI too, I dont know if that will help stop the rasp or not but combined with the CBE resonators that should keep it more quiet than those without the HFC resonators. I thought about theirs but the price is too steep for me so I will be going ERZ HFCs combined with my FI CBE. Should sound good. With the way my FI CBE with 12 resonators sounds right now, which is about perfect, not too loud but loud enough that it gets noticed and no rasp, if you go FI CBE 12 resonaotrs and FI resonated HFCs you will like the sound as it should be loud but not ricer loud.

Since you stated that you plan on going with our exhaust system I have a recommendation. If you really want to keep a HFC of some sort but want to cut down on the hiss during deceleration here is what I recommend.

First and foremost go with our stainless steel muffler option and 18" resonators in the x pipe itself. As far as the high flow cats, ours are 300 cell just like the Berk as well as Stillen. However, we offer a resonated high flow cat that no one else does. What this does is give you a high flow cat and resonated test pipes all in one. The beauty is, they do not make any less power than our 300 cell high flow cats. The resonator is straight through perforated core and in my opinion will help cut down that hiss that you are hearing.

It is there even when the exhaust is stock and if you listen real closely you can hear it ever so faint that it is. By removing the stock cats which use higher cell count cores and thicker exterior material, you eliminate what is absorbing most of that sound. All of the HFC's on the market are less restrictive than stock and much lighter because we use thinner wall tubing. This is why this sound becomes so much prevalent.

If you have any questions, please do not hesitate to ask...

Thank you, Tony

Be careful going with a HFC that uses a 200 cell cat. They are less restrictive and will be LOUDER than ours. I know that ours are more expensive but when you first came to me you told me that you wanted the quietest option available. Our resonated high flow cats are it. In the end whatever you decide to go with, I do hope that it works for you. I just wanted to put my 2 cents in...

Thanks, Tony

No problem, I dont want too loud (which is why I wont do test pipes or LTHs) but I dont want too expensive either. For me price is at the top of the priority list with performance and quality. Id love to have the res HFC but its just too steep for me for the gains. Love the CBE tho.

berk and stillen are 300 cell counts too? I thought they were 200 cell counts.

If the money is the top priority then go with just a high flow cats. They are $120 less than the res. HFC's...

Thanks, Tony

Thanks for the info, clears up quite a bit of questions for me!

Thanks, Tony for all that information! But which would be better as far as the deep tone: the res. HFC or the regular HFC? I want to cut down on the hiss but I'd like a nice deep tone too if that's possible. If there isn't a way to do that than maybe I'll just deal with that hiss.

The FI CBE will take care of that. It's the deepest there is, even with HFCs or Test Pipes... it's nuts.

Do a search for a post by forum member "Valentino". He has some high speed pass clips with his FI test pipes and 18" CBE... it sounds so wicked!!!

The Res HFC's are deeper and smoother. It is the resonator itself that attributes to most of that.

Thanks guys!!!! Now that I know I'm going for the res HFC's and CBE..now I just gotta sell my stock exhaust and the Nismo S-tune exhaust with Stillen HFC's. If yall know of anyone who's looking for either, let me know.

Also..for the res HFC, placing my order for them it says pick one Extra O2 bung: passenger, driver, or both pipes. What are these 02 bungs?

One other thing you also might want to consider is whether or not the HFC will give a CEL. I have had the F.I. HFCs on for about 8000 miles now and not a single CEL.