Originally Posted by MaDMaXX

The S-tune is an upgrade for the road, it is freer flowing than stock, but it's still a multi-chambered system.

It's marginally louder than stock with a good note, but performance is only marginally better than stock as well.
Bear in mind that the s-tune is also deep, so if you're after a higher pitched sound, maybe the injen would be more suited.
Though for power, the HR y-pipe is just a poor mans bandaid. It's not a fix for the problems with the stock y-pipes (poor merge collector and poor crush bends) I would suggest a MD XYZ pipe for the flow and benefits.

Originally Posted by Jairen

^this. Suggest the XYZ y-pipe for maximum performance.

The muffler isn't straight through and will be similiar to this pictured below.


If your not going for maximum performance and just using it to "floss" around in, the S-tune should be fine.

Originally Posted by Sylvan lake V35

Injen sounds gross, the first time I heard one I felt sorry for the guy that just bought it. Spending money to make your car sound that way is sad. For true dual Stillen is the best sounding in my opinion. You won't see huge gains from exhaust on these cars so I would go with something you like the sound of 5-10whp isn't enough to even notice so don't let it effect your decision.