Which exhaust should I choose

A friend of mine did too and ended up not running correct and to had to have the computer tuned for the upgrade. Cost a lot of money and had to go back for more tunes after that a few times a year, it was never the same after that and ran like dog doo doo.

Hm, well I'm pretty sure since I wouldn't be replacing the downpipe that I wouldn't need a tune for it, what exactly did he get on his impreza?

Ask before buying if tunes are recommended afterwards which for Subaru I can tell you their exhaust is highly tunes for their application and unless your doing engine mods you will get very little if any and can loose power from changing it, now it want a new muffler or catback or tips go for it and no worries (Go For It) . He took it to GA from AL for the tune after the exhaust system install and it ran poor the whole way. I do not know if he replaced down pipe ect. I do know he took it to a shop for the install here locally, and after it did not run correctly and they did not do tunes there so may have been from header all the way to tip but when I say new exhaust system I think all of the exhaust not just pipes & mufflers & tips as you get very little benefit from it, shop said they did not do tunes for it and the closest place was a 3 hours away they recommended him too.

If your not wanting to change but the mufflers & tips ect then no tune needed. If your taking out the old from head to tip then yes you need a tune for that.

The only proper way to custom tune an engine is on a dynamometer. If your speed shop is doing it by guess and by golly you are going to be disappointed.