2017 800 teryx

hi folks, we have a 800 teryx the cat plugged up . fixed that but now the machines top speed is only 65kmh.
we use to get 80kmh. the fuel filter has been changed . a new check valve put on the gas tank with new vent filter. before we found out the cat was plugged, we though the lag in power was the fuel filter .that was not the problem. bought the machine new just over 10k km. love it .
help please ?