Just wanted to let anyone how cares know I'm about to make an exhaust system for my 08 Astra. I'll be using 304..16 gauge. Its in the first stages. I'll be buying my piping from Stainlessheaders.com. They have great prices on their 304. I'll be taking pictures in steps as I'll be making and welding this in myself. I'm not really sure what I'm going to use for a muffler yet. Cause I DO NOT want the pinging high pitch muffler. I'm think about a 12 inch resonator or something with a muffler. But anyway, stay tuned there are more posts to come!

 

How large piping do you plan on going, and are you doing full headers or from cat back? Please do post pics.

IMO; Resonator is a must. When I had the headers done on my s series, they removed the resonator and it sounded like hell. Loud, ricey, high pitched. I threw a small (i think 20" or so) one on there and it leveled the sound out nicely.
My car sounds just fine on a turbo muffler. Magnaflow and flowmaster have decent sounding mufflers as well.
(obx header 2" from collector to res then muffler and "3 tip off muffler)
(this video is becoming ever more useful by the day lol)

 

I know I want to HEAR this when you get it done, so be sure to post a sound clip ....

 

Not a problem.. Will do!

 

I'm going to be building a cat back system. As for the size pipe I'm going to use.. I'm not even sure what size is stock on the car but I was thinking of using 2.25 inch pipe. Def going to keep the stock tip to keep it looking stock. I'm going to make it as quiet as possible while picking up as much power as possible.