I would say that has more to do with mixing than mastering. What different soundsystems provide is essentially different attenuation or accentuation of different frequencies in the spectrum. So, for example, if you want a mix to sound "bass heavy" on a crappy laptop soundsystem, you could try boosting the harmonics of the bass instrument, for example. If you want your music to really show some extra depth on a system with proper low-end, on the other hand, you can do this by keeping the lower parts of the spectrum with some "musical integrity", i.e. not just as an enforcement of things going on higher up.