Way the fuck off topic. But, yes. You are almost 100% right.
Depending on the NA motor it is. Less back pressure 90% of the time results in less torque.
On internal waste gate turbo motors. You need no cat for back pressure.
Do NOT argue me with that.
As for the sound. Depends on the motor. A SBC, a 4.3L, a RB series, UZZ all sounds fucking redonkulous with punched catties.