What to watch out for when buying parts

Im looking to do some exterior mods on my 335i and i am fairly new to all this (grill, splitter, spoiler, diffuser,exhuast all that good stuff) and im the type of person to search for things for hours on end to find the best price. One place that i look at often is ebay and i always wonder why the prices are always different. for example i found a black kidney grill from $114( the first option) and another for $60! both the sellers have great feedback too. So im wondering, is there a difference between the two? is one possibly fake?



should i just spend a few more bucks and buy the parts from a site like getbmwparts.com which i believe is legit.



also, thoughts on just plastidipping my front grill?



if these questions are stupid please go easy on me im just a noobie trying to learn :-)