I ordered a Forester specific muffler from Scott at Stromung (http://www.stromung.com). It is 2.25" piping with around a 3.5" tip (I haven't measured the tip).

Installing it should only take 30 minutes or so, and it is easier if you have help, but can be done by yourself.

Begin by spraying WD40 or similar product on the 3 hangers that support the muffler section of the exhaust. While that soaks in remove the 14mm nuts and bolts that attach the muffler section to the mid-pipe, be sure to remove the gasket as well. Then begin removing the muffler from the hangers working from the front of the car to the rear. When you get to the two at the rear bumper be careful to not drop the exhaust as it will fall down as soon as they are removed. Install the new muffler in the reverse order. I used the supplied 17mm nuts and bolts and gasket instead of reusing the old ones.

Wow! It is louder than I expected (I also have the Borla header). Scott told me that the Forester exhaust turns out louder than the Impreza one for some reason. It is intrusive when you get on it. That being said, I love it. My wife likes the way it sounds as well, but she is into cars so you may not get the same reaction from your significant other. It has a very distinct boxer rumble now.

http://www.azscooby.com/images/scoobymods/forester_stromung.jpg
http://www.azscooby.com/images/scoobymods/forester_stromung1.jpg

I will post a sound clip when I get it online.

Regards,

Aaron