The brake job should be a piece of cake. Nothing special to it. You're looking at $40 - $55 per rotor on the low end/OEM replacement. High performance stuff can run pretty expensive, though. Pads will run $30 to $40 for OEM providers, and more expensive for the fancy stuff. I would stay away from Ate, since they generate so much dust that it will look like you drive through a coal mine on a daily basis. The wear sensor will be an extra $10 at most.
As far as a chip, The Jim Conforti chip through Turner Motor Sports is a popular and reputable choice: Turner Motorsport | BMW*E34*Performance Chips: 1985-1995 Cars
It will run you $250 and the expected gains for your car are 22 hp @ 6000 rpm, 20 ft-lb torque @ 4000 rpm, and the rev limiter is lifted to 7000 rpm. Worth the money if you ask me.