There's also MPFabs "anaconda" that is the DP and midpipe section with a high flow cat... It'd be my choice.
As to the comment of why change the exhaust, there are several.
1. Power, there are substantial gains by switching to a freer flow/better tuned exhaust.
2. Sound. This is subjective but some people like the exhaust to be loud, change the pitch, or even hear the engine a little bit.
3. Easier take off (manual trans). The Sonic has some peculiar nannies that make taking off different than many other manual cars. Being able to hear the engine is a godsend in this regard.
Btw have you listened to any exhaust vids of the 1.4t? I'm assuming no otherwise you wouldnt compare it to a vehicle with an exhaust leak or an old straight piped pickup..
Nothing wrong with not likening louder than factory exhaust, It's just another flavor. But there's some reasons people swap out exhaust components.