I used to like Aurora heims (good enough for the nasa and the military). They actually aint priced bad, real good quality, and tons of options
http://www.aurorabearing.com/
This place used to have the best prices on them but it's been awhile since I've shopped around.
http://www.midwestcontrol.com/
On the a-arms I would pony up for chrome moly. Something like that I don't think there is such a thing as overkill.