there are tons of sites to get aftermarket parts from.
I can also recommend HighPerformanceBulbs.com for some unique choices for lighting (stuff E92lighting.com doesn't carry)
of course, there's always ebay... if you are looking for OEM parts though, try finding the part number and searching directly for that in ebay and you may save some money that way for finding the same part (you may get free shipping also)
**********s.com also carries a wide variety of accessories
WTB: 3 Stage Intake Manifold and components - PM me your asking price.