If you have enough truck (front brakes) then...
"...the truth is that today's disc/drum setups are completely adequate for the majority of new cars. Remember that both disc and drum brake design has been vastly improved in the last 20 years. In fact, the current rear drum brake systems on today's cars would provide better stopping performance then the front disc setups of the '70s. And today's front disc brakes are truly exceptional in terms of stopping power. Combined with the fact that between 60 and 90 percent of a vehicle's stopping power comes from the front wheels, it's clear that a well-designed, modern drum brake is all that's required for most rear wheel brake duty."