I did mine by drilling 3 1" holes in the top and not cutting the L.You can plug the holes up with rubber grommets to reverse it.
Did it make a difference ....you bet.Although i have a aftermarket exhaust and different jets & needle height.The mods i did were with the instructions for the pipe to get the best results after fitting the pipe.
Yep i'm some kind of dummy
Take the green pill or the red pill- the choice is yours;This is your last chance. After this, there is no turning back. You take the blue pill - the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill - you stay in Wonderland and I show you how deep the rabbit-hole goes.