Recently bought an 09 c6 z51. It’s has kooks long tubes with kooks 3” catless x pipe kit and a stock z06 NPP muffler (valves permanently open)I like the sound but the drone is pretty bad. I’m thinking about replacing the mufflers with something else. Would a muffler delete be too loud with the current set up? Or should a try a different set of mufflers? Thanks for any advice

 

Welcome to the forum. Straight pipes with no cats and mufflers would definitely be louder. Can you reengage the NPP valves? Or you could check with Kooks to see if they make a muffler for your setup.

 

The drone on a muffler delete is going to be worse than NPP’s with the valves open.

 

I have been looking around at muffler to replace factory muffler on my 2007 coupe, which is very quiet. Billy Boat makes system that is not too loud until you get on the accelerator. They say no drone. PRT 0425 Hope this helps.