I've been on a bit of an exhaust journey so hoping somebody can learn from my experience.
My Selection Process:
I listened to a ton of videos online and narrowed it down to Borla and AWE. The ability to retain a stock-like quiet mode was what pushed me to get Borla over AWE. Ultimately, I went Borla S-Type because I liked the slightly smoother and deeper tone vs ATAK.
I've had positive experiences with some of the newer Borla products that have (near) zero drone but still provide a smooth deep sound. I've also noticed Borla does a better job managing the transitions between 4-cyl and 8-cyl modes than some of the Corsa and other aftermarket systems I've experienced.
Borla S-Type Impressions vs Stock:
1. It’s noticeably louder than stock but not obnoxiously so.
2. It sounds much deeper than stock. Smoother and more bass heavy sound character. I really like the tone.
3. Quiet mode works well. Not as silent as stock but definitely still a real and very effective quiet mode.
4. The black tips and muffler are tucked up much higher and a lot better looking than stock.
5. It manages the sound in V4 mode well. The transition is a bit more pronounced than stock, but very well managed. I’ve had and heard other vehicles with cylinder deactivation and aftermarket exhaust that were way more annoying in the transition between V8 and V4.
My Problem with Borla S-Type (drone):
I had some boom and drone that peaked right around 1900 RPM (120 Hz tone). It’s not obnoxious but it’s definitely noticeable and enough to be bothersome.
The boom sensation / drone is more pronounced in the rear seat. Others might be a bit less sensitive than I am, but it’s noticeable. See screen shot from spectrum analyzer app - it’s the peak right around 120Hz that is most problematic (green part of chart, not red part).
My Drone Solution (MRT ProSound):
I called a bunch of aftermarket exhaust shops to try to resolve this specific drone issue. I wanted a targeted solution - not just adding resonators to quiet it down and mask the issue. My goal was to preserve the sound character while targeting the specific frequency. Space under the car is limited which also presents a challenge.
Ultimately MRT was the shop I worked with and completely solved my problem. MRT was awesome to work with and they knew exactly how to solve the specific issue I had. They recommended their ProSound mufflers because they were designed to target the 1900 RPM drone I was having. My issue wasn't specific to 4-cyl mode, it was happening in V8 mode right around 1900 RPM.
The MRT ProSound mufflers were welded in and replaced the Borla mid muffler & switch fire crossover section. I retained the Borla S-Type rear muffler. These MRT ProSound mufflers specifically target the 120 Hz drone that occurs around 1900 RPM in V8 engines and work as advertised. The "after" spectrum analyzer graph doesn't have the same peak at 120 Hz.
Overall I like the modified Borla + MRT exhaust even better than before! It's the perfect balance performance sound and zero drone. Makes the system easier to live with every day.
Borla S-Type with MRT ProSound Mufflers in Mid Section Impressions:
1. Overall it sounds a touch deeper than regular Borla S-Type but still retained a strong performance sound.
2. It’s a bit more mellow below 2.5k RPM but wakes up above 2.5k RPM and doesn’t seem to have lost much volume there. Perfect balance IMO.
3. Has a deep performance tone at all RPMs but volume levels build a more gradually than before which makes the system overall more enjoyable to me.
4. It smoothed out the booming drone tones that happened around 1900 RPM (specifically the 120 Hz / 1900 RPM peak).
5. The transition between 4 cylinder and 8 cylinder mode is less pronounced than with the regular Borla system. It was OK before but this is a noticeable improvement.
6. Quiet mode is slightly quieter now and sounds exactly like stock quiet mode.
7. MRT did the install and the welding and the quality of their work was amazing - all 304 stainless and excellent quality welds
