G8X M3 | M4 Center Exit Valved Catback ExhaustG8X M3 M4 Catback Valved Exhaust System Unleash a Deeper, More Aggressive Roar Transform the sound and performance of your G8X M3 or M4 with our 3. 5" Full Catback Exhaust System. Designed to unlock the full potential of your vehicles S58 engine, this system provides a dramatically deeper, more resonant exhaust note, ensuring your car sounds as powerful as it performsall without the need to cut into your factory exhaust. Pair this Center Exit Exhaust