New owner looking for advice

[T.O. Realtor]

Hey guys,

I'm about to go shopping for a used 3 series and I'm trying to decide which model to go after but I don't know the main differences, aside from the engine.

Are there any years to avoid between 99-05? I have a friend who is a wholesaler going to auctions for me over the next few days so I want to be as specific as possible.

Thanks and I hope to be part of the family soon!

-Scott