A muffler or axle back will give you a slight increase in power, they will also give you a nice tone depending on what axle back you purchase. The blitz is fairly loud and an example of the quiet would be the prodrive, stromung...so on and so fourth....

A catback will bolt strait up to your downpipe (depending on what catback you get,might have to get an adapter) and will take out the intermediate pipe and the muffler. You will get a nice boost of power and a little bit more sound than just getting a muffler....

either way you will get a nice tone and a power increase. If you want to go turbo back in the future both of these options can lead you there. Personally i would go with and axle back and then later get a Turbo XS stealth back...

The axle back is cheaper but it is all up to you and what you want to do, But if you have the money i would say get a full turbo back(alot more power) like the B&B or the T-XS...

I have the T-XS stealth back with a Stromung twin tip...really nice boxer note not to loud and not to quiet...

good luck, hope this helped you out

 

here is a very good diagram showing all the exhaust components.

https://www.i-club.com/forums/showth...xhaust+diagram