The factory used resonators infront of the axle and mufflers at the back(beside the gas tank) on all engines with dual exhaust. The resonator hangers mount to brackets either welded or bolted to the floorpan. Some cars used a bolt-on hanger on the shock x-member. The rear muffler hangers mount to the trunk floor. There are brackets that stick down through the floor that the hangers mount to. There are S-brackets that connect the mufflers to the hanger.
A lot of aftermarket systems do away with the resonators. They install mufflers before the axle and just run a pipe along side the gas tank. Is that how your system is designed? If it is, you'll have to make some hanger straps to weld to your tailpipes.
I have no personal experience with Pypes systems but I've read some reviews where people weren't very pleased with them. You can always take the system to an exhaust shop to have it installed. It's possible that the pipes need to be tweeked a little here and there to fit.