🚗 Borla 40351 Performance Muffler Review

Bought to replace 28 year old turbo mufflers (universal brand). I was expecting Borla mufflers to be louder, but they have a really nice tone when you step on the pedal. I didn't hear any difference in the sound at idle, but it depends on which muffler you're replacing. Engine 355 SBC.

Used on Miata for autocross to reduce weight and noise. It works amazingly well, nice and quiet even without using a resonator. It has a very quiet rumble at idle and no squeaks at full throttle. I actually wanted more sound, but I'm pleasantly surprised at how quiet it is.

Installed these mufflers Borla 40351 on my Lexus gs350. Unfortunately, there's a decent amount of "low hum/hum" from the drone at around 2-3,000 rpm, which equates to 70-80 speeds on the freeway. I used to remove the muffler and it was louder, but all the reviews online and on forums said they have no hum. 1500 km driven, the noise is the same. Can reset normal silencers, time will tell. I also had a Helmholtz resonator welded on, which didn't help much even after calculating the required…