APEXBUILT GESI Cattted Downpipes BMW F97 X3M & F98 X4M (S58, 2021+)

ApexBuilt® F9X X3M/X4M Downpipes offer...

• No check engine light on factory-tuned vehicles.  

• 49 state emissions legal* 

• Industry-leading build quality.

• Perfect fitment, guaranteed.

• Drastically improved throttle response, quicker turbo spool, and an aggressive exhaust note versus OEM.

• Estimated gains of 20-25+ wheel horsepower and 40-50+ TQ when installed on a vehicle that is not tuned.

• Estimated gains of 45+ HP and 60+ TQ over stock power levels when paired with an aftermarket ECU tune.

• TIG-welded T304 stainless steel construction, assembled by hand in Naples FL.

• EPA approved GESI GEN2 UHO metal-core 400cpsi 4.5" cats, rated for 500-800hp applications & road legal in 49 states. 

• Lifetime warranty.