If you could do either a 3inch catback with a straight thru muffler, or a 3inch downpipe which replaces the cat. What would give you more performance and a louder sound out of a 98 eclipse gst with stage 1 mods?

remember for those of you who are just going to say do both, thats not the question. I know doing both would be best. I'm asking which step offers the best gains. Thankyou

 

you cant pu the 3" downpipe first becuase that would be bigger than the stock piping and you would create some backpressure. Catback always first

 

thanks that makes sense. I already have a 2.5inch muffler/resonator for the back, so if I we 2.75inch piping from the cat back and got rid of the two stock resonator would that be good? or could I go 3 inch to the back 2.5 muffler, its straight through, about 12 inch long.