Ok...so I think I am going to break-down and buy some slip-ins to use on special occasions where the DNR/lake patrol like to be present. I am looking at Eddie Marine Double X and Livorsi LIVORSI. Eddie Marine claims "up to 12 dB reduction" while the Livorsi testing "showed reduced sound of 4-5 dB".

Why would one be better than the other? Will these affect performance and if so, how significantly?

GGB has some new slip-ins, which I'm considering: check their web site. www.gba.ca
Due

Ummm...Due....that link takes me to Golden Basketball Association.....what's up?

So I figured it out...your link is misspelled and it's located at www.ggb.ca. Their slip in's are considerably more than the ones I listed. Their products look nice but am wondering if the price difference is worth it? 4" inserts are $289 versus $73 from Livorsi....is a huge difference. Of course if they are truly that much better, than perhaps they are worth it!

how can they be worth it???If they are slip in and for special occasions when Larry law may be around the difference can only be performance...right? If I worried about a noise ticket I'm sure not looking for every HP.....

dyno,

Interesting point....don't we want the best of both worlds for performance AND to be legal? I do worry about a noise ticket and performance....the question that I have is which slip in is better, Livorsi or Eddie Marine? If performance falls off a bit with the insert, it's acceptable if the net result keeps the water patrol from issuing me a ticket. Which one get's me to a legal level with the best performance?

Those "Double X" Slip ins will definetly reduce your power. The louver insert looked interesting. They do reduce the id of your exhaust by an inch (?). I wonder how that would affect things.

You could also consider CMI. They have simple clamp on muffler that is also good the 10db.

Cord,

Any idea on price for the CMI clamp on? I figured that the reduction in diameter would hinder performance but want to make sure that if I buy either of them that they reduce the dB down to legal level. If they don't reduce it enough, no sense of even putting them in. I have silent choice right now but just want to avoid complications with the DNR....am thinking of heading to Lake Winnebago and have heard that the DNR are pretty strict. Will also be heading to the Mississippi River in August for the Miss/St. Croix poker run and have heard the St. Croix area is tough with water patrol.

Sorry about the spelling on that site: too much on my mind today.
The X style (cheap) is out for me because HP is important. I want the mufflers full time. The headers/tailpipes for my boat are CMI custom step/big tubes with custom side by side (welded together) tailpipes with integral H pipe and they're "dry" to the tip. Although the noise enforcement is minimal here, I want to be a "good" neighbor. I love the sound of open/dry headers, but not in a residential area.
Due

Due,

Sounds like for your application the ggb would work the best. Since mine will be temporary, I'm thinking that possibly the Eddie or Livorsi will work. If it affects horsepower too much perhaps I'll go with something like the GGB style.