Wow, those are all really 2.25"?? How do they get the gains out of them that they do by just making a system with different mufflers?....The stock SVT system is mandrel bent, so no real gains to be had there...replace the mufflers and res (or no res) and logic says you should be up there in the 6-8 whp gains they get from cat backs....something doesn't add up here...