As the pioneer of quiet performance mufflers, FMF raised the bar again in 2007 with the second generation of Q series mufflers, the Q4. Built from the ground up, the Q4 is a completely new design, engineered for maximum performance while maintaining a sound level at or near 93 dB on most models. The Q4 is the market leader for low sound / high performance. Less sound equals more ground. Q4 Details: The Q4 incorporates Factory Forward Engineering to move the muffler closer - centralizing the mass for improved handling characteristics. The new Hi-Flo formed end cap reduces weight and is less prone to damage. The Q4 has an anodized aluminum canister and is lighter and quieter than the original Q model slip-on. All Q4 exhausts utilize a maintenance-free USFS-approved turbine type spark arrestor so there is no screen to clean or burn out. The Q4 employs free-flowing internal baffles and chambers, advanced sound-absorbing materials and a reduced weight. Max Sound output 96 dB, most models below 93 dB. Constructed from aircraft-grade aluminum and high-strength stainless steel. Use with stock or FMF header.
"I installed the Q4 after trying a Two Brothers pipe for a while. The TBs VALLE unit was a monster torquey pipe, but was insane loud. The Q4 is not quite as tourquey, but was a heak of a lot easier to tune. No pop, surge, or mad neighbors.