Best Stock dual tip muffler? GS Spyder or GST

[k_dog007]

hey all, I was wondering which muffler is better, the gs spyder dual tip or the gst? I have tips I want to put on them and I need a quite one for my nt. But I also want good flow but not the ticket getting loudness. Also, is the muffler itself swappable or do I need the cat back?

 

[Denji]

i am almost positive they are the same muffler.