It's possible that you needed to undo the two screws holding in the headlights and just nudge them out a quarter-inch for a second to get the aftermarket corners to slide in. That's what I did, and they fit perfectly now.
I bought my 330ci in January of this year with 45,000 miles on it for $17,900 (manual, sport/premium packages, sunroof delete). It was relatively underpriced, so I flew from Atlanta to Miami to buy it and then drove it back. I had a BMW specialist in Miami give it a full prepurchase inspection, and he said it was in excellent shape overall and had a gapless service history, clean Carfax and zero evidence of paint work. Good enough for me.
Factoring in airfare from Atlanta to Miami (only $140 on 12 hours' notice!) gas costs for the drive home ($200 or so, but I criss-crossed Florida visiting friends and showing off the new ride) and new rear tires (they were 75% worn when I bought it), it came out to about $18,600 all said -- still not a bad deal. I haven't had a day of trouble with it, and have absolutely no regrets.