Standard downpipe has a 3 inch olive connector at the end. Some cat manufacturers such as scorpion use the same. Dreamscience cat can be purchased with an additional connector as can the Miltek one. Have a look on the cobra website. It should tell you on there what is on the end of their system.
Collins Cp2 map. Ramair induction. Mountune mud flaps. Scorpion Sports Cat. Scorpion Tracker. Wind deflectors. NB washer jets and shark fin aerial. EBC Grooved discs, YellowStuff pads. Airtec Intercooler, Miltek cat back with titanium tips. Collins quickshift. DSC Controller