Yes, I did it and have had no problems since. You need to get all of the old stuff out, I flushed at least 2 quarts of dot 5 thru. Do you have outboard brakes on the back? that helped a lot also, i put brembos back there.
I have the stock single brake with a oversize rotor that definetly made a big improvement.Did you just mod your stock uprights for the brembos ore buy later model ones.I have thought about this mod but have also seen alot of issues with rocks in the wheels.
I machined the stock uprights and front hubs and made my own caliper mounting brackets. i just used a brembofront kit for 12" wheels. It has a ton more braking in the back now. Rocks are definatly a cause for concern, I have seen a couple wheels worn thru. Hasn't happened to me, but I rarely get to race.