My opinion but the 2.5 DP with plog is good if you are only doing minor bolt-ons with no future upgrades. If you plan on doing further mods I would recommend skipping the dp and running headers. $200 Speed Daddys on Ebay.
On my 04 GT when I replaced the catback I used an air rachet on the bolts between the resonator and DP. They were very rusty and they just stripped. Grabbed a grinder, zipped the head off, and knocked them out. Very rusty. I had new ones ready so be expected for them to break, rusted solid, and fight you. I tried to torch them with oxy/acl to loosen but they were too rusted to come out. Just stripped out.
