I have a Magnaflow straight through on my RX7. It sounds great, but freeway drone is horrible. This is probably due to 70 MPH being 3500 RPM on this car. I love the sound when gassing it however. Exhaust is a short header, presilencer, straight back to muffler. I feel the need to add something like a resonator or glass pack in the straight section to see if it helps. I imagine if I wasn't at such high RPM all the time it wouldn't be so bad. Cruising in 5th at under 55mph isn't near as bad as over 60.