Congrats on your new exhaust system...it's definitely one of the best out there...

 

I put Magnaflow on my 2006 SCLB and you have to twist the exhaust to "unlock" it from the cat. I ended up just cutting the system right after the connection from the cat and then twisted the remaining piece off. Hope that helps if you haven't gotten to that step yet!

 

I used the 16612 system, single side exit. I am lazy, local muffler shop installed it for 85 bucks while I drank coffee and watched! I love those guys!