^^Usually that section of the board helps. So does the feature at the top of the page when you're starting a new thread. It pops up threads similar to what you're asking. Google's a cool new concept as well.
ebay and amazon isnt bad, just use half of your brain when buying parts, if a set of coilovers is 30 bucks free shipping, then that should set off a do not buy buzzer in your head, i buy s**t off ebay all the time.
Yeah Amazon's not as bad as ebay imo.
Just look for things like "top-rated seller" and view the seller's track record (fast shipping, customer reviews, etc.) before making a purchase.