I dont know the exact numbers, but I believe the Extreme Flow Cat will flow like over 150 more whatevers unit more than the High Flow Cat. When I get the pictures of them then I believe you'll be impressed. All the Y-pipes in this GB will have the ability to go no-cat even if you don't order the straight pipe. I'll have more information later as Me and Alex are still finishing the Cat-Back GB. I'll post all information as soon as possible. Thanks
