You rarely blow a speaker by giving it too much power. What you need is good, distortion free, high current power, to keep the drivers from being damaged.
Most of the time the amp is really using less than 1 watt of power driving speakers at reasonable volumes. The power reserve is there for amplifying those bass transients. You rarely feed 120 watts of continous power into speakers.
As long as you keep the volumes at reasonable levels, you are fine.