go for Shimano LX arms, not so shit that they fall apart, not so good they cost the earth plus they are pretty slim which gives you more room for pads and a wide rim. I'd really recommend TNN LGV pads if you're running a grind, best performing pads I found plus they are some of the narrowest too which also give more room (room to set up brakes is a good send at times).
I'd also highly recommend getting a booster, the brakes won't half as good without one.