Karbonius has test-fitted the plenum and made a video, as well as videos of the same car with a completely stock intake and the same car with their CSL-style intake. I've posted the videos below. Karbonius are on holiday until 30 August but provided a few comments when they sent me the videos:
"I just sent you 3 videos,
1- OEM airbox, you can see the results in dB , minimum 72,2 and maximum at 5000 rpm 106 dB
2- CSL airbox , minimum 79 , maximum at 5000 rpm 130.2 dB
3 -Karbonius OEM style airbox, minimum 74,3 , maximum at 5000 rpm 118,7 db.
Sorry for the quality of the video, maybe doesn'tīdo justice comparing with real sound, but I think you can hear the difference between the 3 boxes.
We have 2 dB more in the low measure and +12,7 dB in the revolutioned measurement . The Karbonius OEm style airbox is not as louder as the CSL airbox, but clearly louder than the OEM one.
We checked on the car and drove few kilometers, and we could hear clear the sound of the box, specially between 2500 to 4000 rpm, driving at few rpm and putting gas in 4th or 5th gear is easy to heard."
I also asked a couple of questions:
Q. Will the price be the same as originally estimated (1,200 euro)?
A. Yes , at the moment we will keep the price, but Iīll confirm you when we will make the 2nd unit!
Q. How long will it take to put into production?
A. We can start the production in middle of September
Videos:
Karbonius carbon fibre S54 plenum
https://youtube.com/shorts/NtCRPz1705A?feature=share
Karbonius CSL-style intake
https://youtube.com/shorts/D8S_IVLXTEc?feature=share
OEM
https://youtube.com/shorts/LV8jRFmXMyg?feature=share