Upper control arm bracing?

i wouldn't bother. the benefits that you *might* see would be so minuscule and mostly negated by the stock rubber or poly arm bushings due to their flex.

if it's something of concern, then i'd go tubular with heim joints.

but honestly unless you've got massive tires that are transmitting a ton of load and the rest of the components to back that up: t-bars, shocks and bracing and the car is designed to be pushed i wouldn't bother.