Hey there...
I've been doing the same for my yet to be ordered F10 lol and its not easy. Its much harder trying to find a wheel that suits the F10 body compared to the 3 series. You can't get something that is too tuner looking or it cheapens the car.
With a 3K budget (wheels alone) there isn't many options. Used would be your best bet. Stay away from VMR (cheap replica wheel companies in general) if you plan on going bigger than 19"s. You might save money in the beginning but i assure you they will bend or crack if the roads where you live isn't pristine.
Buy the strongest wheel you can afford without making the car look ghetto is my recommendation. Lots of companies don't disclose openly how their wheels are made and wrap themselves around fancy advertisements so just do your research and ask the question. How are your wheels made?
(Weakest to Strongest)
Gravity Cast --> Low Pressure Cast (LPC) --> Form Flow --> Forged
good link that explains all this info
http://www.tirerack.com/wheels/tech/....jsp?techid=90
Alan