Seriously, buy a hole saw slightly smaller than the exhaust outlet. The numbers are worn off mine but I think its 1 3/4". Drill thru the weld ring inside the outlet and pull the guts out.
My local HD shop did this for years for $20. You do need a good drill, preferable air-powered. The resulting sound is great. Not as loud as an aftermarket system, but throatier.
I told you those short pipes would be loud, that's why I recommended the longer V&H pipes. I'm sure you'll wish you listened to me when those pipes are roaring right next to your ear when you're out riding for a few hours straight.
Ya that's a good answer... Spend another 15 to 30K on a bigger bike instead of just adding some new slip on's or pipes for a couple of hundred... I guess you missed the sticky post on the Sportster being a girls bike...
Get a 2 foot piece of re-bar and sharpen it to a point on one end. Insert it into each muffler and wack it with a hammer until it "punches the baffle". Opens up the mufflers, gives you more sound, costs nothing. This will get you by while you are saving up for future mods.
The cheap bastard in me loves that idea... going to go do it now.
fattony buy you some cycle shack tapered slipons from dennis kirk for $179 best money I spent! they sound totally awesome and turned heads at the local bike night! of course mine is carbed so I can lower the idle and really get them cranking some Harley lope! jmo