2 HP increase dyno proven performance. 88 decibels or less at 4000 rpm. Uses stock springs and hangers. Flo-bench tested for back pressure. XS Chassis 1200 4-TEC XS All models. MX Z Blizzard 4-TEC 1200. MX Z X 4-TEC 1200. Grand Touring SE 4-TEC 1200. MX Z TNT 4-TEC 1200. Grand Touring LE 4-TEC 1200.