I have a 2004 staggered with 525 EFI's and trying to figure out the muffler systems that will make 88 db and not hurt the engine. With the flaps wide open its 96 db and 88 when closed. I am concerned about the RPM restriction and back pressure. the noise cops are relentless!

I have some HPI's on mine and it is fairly quiet. I am not sure of the actual decibels.

I am not familiar with the HPI's. Can you give me the info so I can research it? I am thinking of going with the CMI clamp on 4x5's as they say it will get down to 85DB's. Looking for someone who has run and tested them on 525 EFI's.

I have some Gibson clamp on that I used a couple time on my 650 LOUD hps. Knocked down the noise A lot. Right up until I lost second drive in one weekend at the Shootout. Damn muffler bearings. Have not been on boat since.

I don't even think that HPI is still around. You should also look at Corsa as well.

Aqua Power Ltd Products

Anyone tried the CMI clamp on mufflers? Web says 85 dbs

yea, I think bblythe is right, they are the same mufflers and they work great

I see the CMI system is like $800 each muffler? times 4....

Talk to Paul at Aqua Power Ltd..
I believe he was part owner of HPI at one time.. I spoke to him late yesterday and already have my quote