It does make it alittle faster...but all the connecting plastics under your seat that are held by the airbox will either have to go OR mounted with fabricated brackets...or they make a freak kit...but I dont think its that cheap from what I remember. It's @ newspeedmaster.com
Also...you can always wrap your headers with black exhaust wrap or just paint the whole exhaust with high temp paint...
you can bang out a couple baffles from your stock silencers ( there are 4 baffles in each pipe) 2 out will give you a nice throaty sound without being obnoxious. (I banged 3 out

)
Remember if you remove the airbox and open up your exhaust you'll have alot more air coming through your motor so you need more gas (rejet the carberators) There's a calculator on this site to tell you what jets you need to install depending on the set up decide to go with.
Hope this helps!
have fun!
- Ryan