These guys speak the truth. I recently ran dual 2.5" pipes to a dual in/dual out magnaflow to replace my single in dual out flowmaster. Granted I used the bigger magnaflow but there was not a lot of improvement for the money I dished out. The truck does run better but not by a huge noticeable difference. The thing I like most is that the magnaflow is deeper and quieter and I no longer have to listen to the fart sound the flowmaster made at higher rpms.