topic has been covered a billion times man, check through the threads and you'll find it.

-diff back=just replaces rear muffler and a bit of piping roughly from diff back

-cat back= replaces all piping from the catalytic converter (bout where the transmission is) back.

you will get little power gain from a non turbo motor. about 2.25inch is plenty for a 2 or 2.5L, dont let anyone tell you otherwise.

Hi,

I'm only a newby here so don't crucify me if I've posted this on the wrong thread - but had to join up and tell you about my recent experience with big bore systems.
Had agonised over replacing the genuine system on my orginal STi wagon for a while, but found a muffler shop in Sydney called Best Mufflers that doesn't just try to talk you into whacking on the biggest loudest ugliest system, and claim massive hp gains.  These guys do the R&D, have pics and sound files of the finished product online and then dyno test to back up their results. See link to this recent MY09 Forester XT system;


http://www.bestmufflers.com/bshop/produ … c667f27bc5

As you can see, this 2.5ltr Forester turbo actually LOST power with the bigger cat back system. In fact Best mufflers talked me out of a more expensive full system for my 2ltr turbo and I'm very glad they did. The new tailpipes they fitted up look and sound great (actually QUIETER over 70-80kmph), offer better low down grunt and throttle response while also letting the thing rev more freely. It's also getting slightly better economy.
Check them out;
http://www.bestmufflers.com/bshop/image … erty_5.jpg
 

I highly recommend this mob - now I just need to find someone as skilled to boost up and tune it.....any tips ??

JUXT wrote:

nothing to add about the system, sounds like you got a good deal though

is your name postie25 because you ride a CT110?