I see you already got it taken care of, but how did you end up getting the old system off at the cat? I would have said take a die grinder to the studs then pry the flange off. That's what I did on mine because they were rusted on there good. Stuff always takes 3x as long as you think it will.

 

Heat + an impact wrench and they came right out. I was surprised they didn't break!

 

DANG. What are my options for replacing the mufflers? Simply get a shop to weld two pipes in there? I may just jerry-rig some old pipe back in there.

 

Here's that long awaited sound clip!! Its a lot louder in person and this was filmed on my iphone!

 

youve got to a few options. you can pull the magnaflow mufflers off. they have a bend to the y, so you have to have a muffler shop bend some pipe for you.

you could get a catless hogan down pipe. bolts in so you can put the old down pipe in for inspection. should pump the volume up a bit, and should make some more power. you may want to get the car tuned after that though. down side is it should throw a code unless you have a o2 sensor and simulator plugged in there.

you could get a cut out manual or electric. i think both are pricey especially since you just spent hundereds on an exhaust. the cutout would have been the way to go if you werent getting an exhaust.

heres videos of mine. the in car videos i had shot were done with my cellphone and they sound like trash. it couldnt pick up all the sounds so i never posted them. its the magnaflow catback with the mufflers removed and 2.5" piping welded in place. i used the magnaflow tips too.

06ss magnaflow catback mufflers removed video by themonteman80 - Photobucket

06ss monte magnaflow catback no mufflers rev video by themonteman80 - Photobucket

 

I have the Dynomax mufflers on mine sounds ok , I had the flowmaster 40 series on a 97 Camaro that sounded good as well but in both cases after about 3500 - 4000 rpms it got a bit raspy in . The bottom line is whatever sounds best to the OP is what is the best for his car, thats why we all have whats called opinions. I have always heard for example that straight pipes are for high school kids or the unemployed that cant afford a real exhaust.
Not meaning to offend.

 

imo it is matter of preferences i would go with flo or magna flo if i had the chance again i would put on the magnaflo on my monty claudia. but i already have a flow on mine but it is up to you what do you like the best.

 

i believe the ops car is a ls4 car, and i dont think rasp is really a concern with a resonator in place. if you can afford a stainless mandrel bent exhaust and u straight pipe it im pretty sure a lack of money isnt the reason. the whole reason why straight piping was brought up is because i was sure the op wasnt going to be happy with the volume level of the magnaflow. also unlike the 3100-3900 montes the ls4 doesnt sound like **** straight piped.

 

i have GENERIC copy cat flowmaster, 3" crushed bend, pacesetters headers, and no cat. you can make the 3100-3900 sound like a V8 but you can not get rid of the rasp sound. mine is cammed, and pnp heads, it sound good idling but i can hear the rasp on the take off.

 

they sound like v8s at idle when they have a an exhaust, unfortunately that all changes when they come up in rpm. your car did sound good, but im sure that your heads/cam affected the sound, and those arent the results you get from a straight piped 3100-3900.