I was wondering how well the stock muffler flows? I would like to put in a higher flow cat and downpipe for less weight/more horsepower and keep the stock muffler. All the exhausts sound to loud and hate the drone I had on my previous car. I know attaching high flow stuff to a possibly restrictive muffler may be a complete waste of money, but how much performance gains will be lost? Anyone?

 

You won't really lose power, but you won't make as much as you should with those parts. Also you'll be shortening the life of your turbo by adding more back pressure/heat.

 

You could do a stealth works muffler. Look at the Works website, they modify the stock muffler to make it flow more.

 

+1 exactly what I was going to recommend.

 

Yup. sounds like you need the stealth works muffler. The stock one is decently restrictive if you look at its design.

 

Check this link out. It is vairable from the cabin and may be what you want
http://xforce.com.au.tmp.anchor.net.au/cars/view_car/29

 

thats freakin awesome. exactly what i need but $400 for a muffler?