Depends on if you care about pissin off the neighbors..... i went past a car WOT on the right side, 2 lane rd,... then they caught back up again, and everyone in the car except the driver had thier hands over thier ears...... lol..... But if you wanted to run with out the vortex, id richen it up a bit, flows alot better..... i ran with out the vortex and spark arrestor for a long time..... it was really really loud......and i wanted better flow and quieter, so i got the quiet core, and was surprised its not so quiet..... lol