My thoughts are that if you are going to paint them, then Ebay is ok. If not, you can tell the difference up close, and if you are OCD like most of us M3 owners, youll not like seeing the discrepancies in the CF lines. OEM look way better in my opinion... Go to McKenna BMW (one of our vendors here) and ask Marco for splitters, mirrors, and rear spoiler. Great deals to be had...
"With great power comes great responsibility." -El-Superbeasto