I did the mod that ktmnate shows and am running 14 disks in my stock exhaust. I used an 1 3/8 hole saw. It definately added some pop in the low end and has a nice sound to it now.
I also removed the charcoal canister, airbox mod (top removed and spacers on the side intake(envision an air scoop on the side), 157.5 main jet, drilled the slide, and raised the needle one notch. Some of it thanks to creeper.
Doing the exhaust mod definately was worth the time and effort.
I'd rather do it than watch it.
Those of you with spouse and SO's know this already, but man give them a big hug, and don't take anything foregranted. - MACK RIP
When 51% of the grasshoppers vote, the ants are screwed.