What's the stock piping on my exhaust, anyone know the size? I plan on going to a muffler shop and getting a custom cat-back on... And what size would be the best to go up to?

But I want to keep the stock muffler, i like the sound and look of it :).

2.25" is the biggest you need and I believe it's the stock size of the piping on your car might be 2.5". If you are looking for the best fit, I would have them do 2.25" all the way back.

And a good rule of thumb for what size you piping you need is you should have at least 1" for every 100hp your car has. (stole that from bobthecow.)

yikes. I might as well leave it stock and find a better sounding muffler. (Not to mention i DO like the exhaust a little louder, not gonna lie...)

Any muffler that isn't ricey i am in the market for... and of course it can't look ridiculous >_<

If you like the look of your stock one then I'd go with either a Dynomax Ultraflow, or a Flowmaster 60 series Deltaflow. Both of them look pretty stock plus they have a nice sound to them and they won't sound either ricery or too ridiculously loud.

Here is the link for a Dynomax Ultraflo so you can look at it.
http://www.dynomax.com/products/ultrafloweld.html

And here is a link to a Flowmaster 60 series Deltaflow and 4 series Deltaflow so you can look at it as well. I gave you the 40 series as well cause I don't believe they make the 60 with the proper inlet/outlet design to fit our cars. But you can have a look. We need an offset inlet and a center or offset outlet.

60 Series
http://www.flowmastermufflers.com/60_series.html

40 series
http://www.flowmastermufflers.com/40_delta.html

I have the 40 on my GS and it sounds pretty amazing paired with my K&N typhoon Short Ram. Only thing you mentioned is you don't want anything too ricery and the 40 will give you a slight "gargle" as the RPM's are dropping. But it's not that bad. Here is actually a link to a video I have of mine so you can hear what a 40 series sounds like on the 4g64.

http://www.youtube.com/watch?v=ljkKxwKEmJ8

Hope this helps and I apologize for the extremely long post.

All 3g eclipses are 2.0 stock

Ok then it's just the outlet on our stock mufflers that are 2.5", but the rest of the piping is 2.0" stock. Got it.

Now they dont make them in stainless steel, but a friend of mine put a Cherry Bomb GlassPack on his. it sounded pretty awesome. (He did his own custom cat-back)

According to the local muffle shop around here, the guy told me that just replacing the muffler doesnt really do a whole lot for sound unless you change the resonators. Mabey he was trying to screw with me. But thats what i was told

If you're talking about just changing the muffler won't do much for improving sound as in it won't be loud and obnoxious like a ricer then he's right. However replacing the stock mufflers with a Dynomax or Flowmaster, or so on, will give you slightly louder and deeper sound than before. It is noticeable, but it's a pleasant noticeability unlike the mufflers Honda people put on their cars. You will be quite happy if you're looking for something a little bit louder and deeper sounding than the stock muffler if you just replace it with a different muffler and that's it.

About how much is it to get a mufler put on by a shop? And to clairify for us stupid people you need a 2inch inlet? thanks..

You need a 2.25 inch inlet. And it will cost about $30+ the price of the muffler to have a shop put a muffler on.

^What he said^