Depends what kind of racing you are doing.

For brakes you need to consider a few things:
1. What wheels are you going to run
2. Minimise strut, caliper and disc weight
3. Minimise brake fade by having big enough brakes.
4. Minimise cost by using commonly available components.

Simplest option is to convert to A10 stanza lower arms and balljoints. Then get some 260Z struts. Use the tops/thrust bearing from the 1200 struts.

Leaving the back drums is fine, they only do 20% of the work, and leaving them alone, provides for a good working handbrake mechanism.

Upgrading to larger drums or discs on the back, should be considered candles on the birthday cake.

there is such a thing as too much brakes on a race track.. On the street, you can never have enough. Handling comes second to stopping power when an emergency stop is required in traffic. $1000/ accident avoided. In my old datto, I avoided several accidents due to good brakes!

ps. if you have crap brakes now, don't be convinced to go all out at this point. Even stock brakes would feel good for you right now.