Hello,
Apologies in advance, as I'm not too savvy or knowledgeable when it comes to cars.
About 6 months ago, I put a Stillen CBE on my 2015 Q40 (this is the exhaust: Stillen Exhaust).
It's been pretty good. Drone (if I understand what drone is) is manageable, but can be a bit annoying at times, and the vibration the car makes at lower RPMs at times (especially when you are in the back seat) can be obnoxious.
A couple weeks ago, I bought Berk HFCs (BT1407 - HFC - MET), and the car does sound nice, but when at around 3-4K RPMs, the rasp is what is making me want to replace the HFC or try to replace something on the exhaust to reduce the rasp. I was poking around online to see those who have similar setups I am running, and clearly videos can be deceiving on what the car will actually sound like. The Stillen CBE with the OEM cats were nice, but I was just looking for something a bit louder, which is why I was looking at HFCs.

So...my question(s):
1. Is there something I can do to reduce the rasp, but keep the Berk HFC? (maybe change something with the Stillen exhaust setup or do some other type of mod?)
When the car is warm, the rasp slightly goes away.
If the Berks are the issue, I was looking at the FI RHC, but I haven't seen (from what I can tell) the Stillen CBE with the FI RHC. I'm not even sure if this setup would be any good and if the OEM cats would be something I should've kept.

2. Has anyone else experienced with the Stillen CBE drone or major vibrations in the car (especially in the backseat)? My only assumption the vibration would be so bad in the back is because the mufflers or resonators are there (again, not a car expert, so please correct me).

3. What exhausts have you seen which pair nicely with the Berk HFC where there is no drone/noticeable rasp (when accelerating to 3-4K RPM)?
I was looking at maybe Topspeed

I have included some videos of what the car sounds like now with Stillen CBE and Berk HFC. Apologies for the audio quality in advance.
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Thanks!

 

bump ... ty

 

an easy way would be to replace the Stillen y pipe with a resonated y pipe.
here a a few options:

Single resonated y pipes =
Motordyne
https://conceptzperformance.com/moto...019_p_8585.php

Z1
https://www.z1motorsports.com/z1-pro...d555788b676e86

Circuit Werks (it says for Z33 350z, but it will work for you Q40)
https://www.ebay.com/itm/121774649330

Then you have dual resonated y pipes:

Hall Built Performance
https://hallbuiltperformance.com/sho...37-q40-and-q50

Thaitanium
his website doesn't have the product but if you are on facebook, you can look up his shop page and buy it through that.

 

Thanks!
Do you think adding in 2 vibrant resonators to the Stillen y-pipe (one on each individual pipe closest to the cats) would be another idea (for budget purposes)?

 

yea, i think resonators there would also work.

 

Cool. Appreciate the input!