2001 325i control arm replacement

[Zebisko]

I have to replace the passenger control arm because of those non-removable ball joints being bad. I would like to know if there are any special tips or tools needed to replace this. I wanted to replace it with a model that has replaceable ball joints, like these from Bavarian Autosport.
http://www.bavauto.com/shop.asp part# 31 12 6 752718M

Now what I wanted to know is if, since it is aluminum, I could replace just one, or if I would have to replace both(betting I will). Also I would like to know any other suggestions for parts cheaper than dealer replacement; control arm($225), also for the control arm bushing(both for $138). Thank you very much in advance.