The popularity of exhaust pipes can vary depending on several factors, including the type of vehicle, personal preferences, and regional trends. However, some of the most popular types of exhaust pipes and exhaust systems include:

1. Single Exit Exhaust: This is the most common type of exhaust system, where there is one exhaust pipe that expels the exhaust gases from the engine. It’s often used in everyday vehicles and is relatively straightforward in design.
2. Dual Exit Exhaust: Dual exit exhaust systems have two exhaust pipes, usually one on each side of the vehicle’s rear. They are often used in sportier or performance-oriented cars and can provide a more aggressive look and sound.
3. Cat-Back Exhaust: A cat-back exhaust system replaces the exhaust components from the catalytic converter to the tailpipe. It’s a popular aftermarket modification for enthusiasts looking to increase performance and change the exhaust note.
4. Axle-Back Exhaust: This type of exhaust system replaces components from the rear axle to the tailpipe. It’s a more budget-friendly option compared to a full cat-back system and can still provide a change in sound and aesthetics.
5. Custom Exhaust: Many car enthusiasts opt for custom exhaust systems, which are designed and built to their specifications. Custom exhausts can be tailored to deliver specific performance gains, sound levels, and aesthetics.
6. Performance Exhausts: Various manufacturers offer performance exhaust systems designed to enhance a vehicle’s horsepower and torque while providing a unique exhaust note. Brands like Borla, MagnaFlow, and Flowmaster are known for their performance exhaust systems.
7. Turbo-Back Exhaust: Typically used in turbocharged vehicles, a turbo-back exhaust replaces the exhaust components from the turbocharger to the tailpipe. It can improve turbo spool-up time and overall performance.

The most popular exhaust pipe or system will depend on the specific needs and preferences of the vehicle owner. Some people prioritize performance gains, while others focus on aesthetics or achieving a particular exhaust sound. Additionally, the popularity of exhaust systems can vary by region and the type of vehicles commonly found in that area.

The “best” exhaust sound is highly subjective and depends on individual preferences. What sounds good to one person may not sound appealing to another. That said, some popular exhaust sounds and characteristics that many enthusiasts appreciate include:

1. Deep and Rumbling: Many people enjoy exhaust notes that are deep and rumbling, giving a sense of power and aggression. This sound is often associated with V8 engines and larger displacement engines.
2. Aggressive and Loud: Some enthusiasts prefer a more aggressive and louder exhaust note that can turn heads and make a statement. This sound is often found in high-performance and sports cars.
3. Throaty and Growling: A throaty and growling exhaust note can be appealing to those who want a combination of power and refinement. This sound is often associated with high-performance European cars.
4. High-Pitched and Exotic: Exotic sports cars and supercars are known for their high-pitched and exotic-sounding exhaust notes. These sounds can be unique and attention-grabbing.
5. Subtle and Quiet: On the other end of the spectrum, some individuals prefer a more subtle and quiet exhaust note, especially in daily driving situations. This is common in luxury cars and hybrids.
6. Pops and Crackles: Some performance exhaust systems are designed to produce pops and crackles during deceleration and gear changes. These sounds can add excitement to the driving experience and are often associated with turbocharged engines.

To achieve the exhaust sound you desire, you can consider aftermarket exhaust systems designed to enhance the sound of your vehicle. Keep in mind that modifying your exhaust system may have legal and emissions-related implications, so it’s important to check local regulations and choose an exhaust system that complies with the law.

Ultimately, the “best” exhaust sound is a matter of personal preference, and what sounds best to you may not sound the same to someone else. It’s a good idea to listen to sound clips and videos of different exhaust systems on your specific make and model of vehicle to get an idea of the sound you prefer before making any modifications.