I want to add exhaust to my truck. I havea 2001 F150 4x4, 5.4l with orp and towpackage. I thought about dual exhaust(true). I thought I might lose too much torque. What about a good catback? Which brand style? I read Gibson says cant have dual rear exit w tow package and may have to move spare on 4x4. Is this true? Does dynomax make a catback? Whe does besides borls, gibson & flowmaster?

Thanks
Don