2011 5.7 exhaust woes

I have a 2011 5.7 SR5 double cab w 8' bed and ordered the magnaflow cat back off road pro, part number 17111 and just found out that it doesn't fit once I opened the box. Even though magnaflow, cariid, summit all say it will fit. It doesn't...not even close. I bought this truck used from a guy in MD that did all maintenance at a dealer and trades in every 3 years, so I don't think he would have done anything weird manifold thru to flanges to where this kit will not fit... He would have used OEM for sure. I just cant believe Ive spent almost 3 weeks on this issue to no avail. I wanted the truck to breathe/exhale better, etc. by going with something better than stock as I have a cold air intake. The flanges on the 17111 kit are parallel w/each other, however the existing flange on drivers side is more on a 45..Anybody else have a 2nd gen 5.7 double cab w/the 8' bed and have experienced the same bs, please help me out! Thanks in advance!