If I had a tac, I'd tell you more specifically but it's absolutely tamable. I'd guess above like 3k or so it explodes but I would have no problem rumbling a full days drive in it. We'll see if that holds true once the adrenaline wears off. Maybe I can secure some interior vs exterior footage if that'd be interesting to folks.
The Magnaflow glasspacks are definitely a better choice than Cherry Bombs IMHO, and the duals, again IMO, keep the rice and rasp at bay. In choosing an exhaust setup, I was comparing to the old 200cu Mustang straight sixes. There's tons of YouTube videos and everyone says split manifold true duals are the way to go.
If in the future it's too loud, adding a rear resonator shouldn't be very difficult, especially since it's all V-Band clamps. Easy removal and install.