I bought a 77k Gray 2006 Mustang just about last week and the car was loud I personally liked it. But I was wondering what system it had. Looks dead stock but cut off mufflers. So down to the question on this exact model what's the effect of the previous owner removing them. On a dead stock setup other than an cold air intake. Its now instead of mufflers a straight wide stainless steel pipe

 

Effect? Nothing, there are several companies selling muffler delete axle backs, which really just get you a section of pipe with a nice tip on the end.

You can get away with muffler deletes as long as you have the stock cats...high flow cats or no cats, forget it.

 

Okay I'm pretty sure its stock I never took a good look but going by a quick peek there's no mufflers but system does seem fully stock