the lamp parts are the same. the difference would be the harness, i don't think the 55w sets come with a relay, so unless you added one yourself, you're going to be running full amps through the firewall and your switch. I think the wiring is thinner on the 55w kits. the higher wattage harness has what looks like 10 or 12 awg primary power. Your fuse at the switch won't protect the wiring at all. For example, if i'm running a 2x100w setup, i would need at 20 amp fuse at least, so if i connected it all with thin 24 awg wiring, the wire would burn up long before the fuse blows. Check your wiring for AWG and look at your switch for 12v amp rating if there's no relay. Anyways, those are things to think about.