Has anyone used these muffler inserts before? They slide into the header collectors/exhaust pipe - but thats all I know about them.

I'm considering these for my 3rdgen... I'm putting a big block into the car in the spring, and because of the header design, its not easy to get a traditional 3rdgen/4thgen style exhaust system on it, so I might have to just run pipes under the floor and then out the sides just ahead of the rear tires.

Ground clearance is a problem under the floor, so I need something really low profile. Its mostly a track car, but will see some time on the street too, so I'd like it to be reasonable.

How loud are they?
Are they restrictive?

These are what I'm talking about... I was thinking about a pair of 3" inserts with the 3-plate setup (what they call the 'street/strip' setup)

 

I used the two disc inserts for a while. I think those are called the race version.
My setup consists of LT headers, ofroad Y pipe into a Borla catback with no restrictor plates.

I really liked the sound of the inserts because they got rid of all the drone and did quiet down the exhaust a bit.

I got rid of them because I am positive they will impose some restriction to the exhaust flow, specially at high RPM. I did not conduct any dyno testing to back that up.

 

That looks like a 3" muffler bearing

 

I have used a single CCI 3 1/2" insert in a Mufflex cat-back system w/ a Spintech muffler. I have no cats now (due to destruction from blower vol). So, lots of resonance or "drone." Installed CCI in pipe before the kick-over. Works great, but, I think i need to weld the small end cap on the center pipe section (the one w/o the hole) to further reduce noise. I use a QTP to by-pass it for max flow. (97ss 383-D1 MM6) B

 

How much of a sound reduction did you guys notice? Being that my setup will be dumped out the sides, I'm not counting on Honda-quiet... just something within reason on the street.