I'm getting ready to wire up two of the same blinglights as the previous poster. I was thinking of going with 100w bulbs instead of the 130w you posted a link to. I'm going to be running the harness that came with them (don't remember the gauge) and I'm wondering if the harness will handle the extra current?? I don't believe the harness has two separate wires to be run to the relay - I think they tie together into one. Come to think of it, I don't remember even seeing a relay with the original harness. If there's not, I'll be putting my own in. I'm also running them to a seperate Blue Sea fuse panel I installed under the hood. So, what's the highest wattage/current you can run with the correct gauge wire??
With what you are suggesting and assuming the harness is most likely 16 GA, technically speaking, the answer is yes you could run two 100W bulbs through 16GA wire as the way it would be done is to wire the two separate leads together at a point that would leave maybe a 4 ft (single), wire run to the relay/block. This calculator i dug up http://search.yahoo.com/r/_ylt=A0oGd.../Wire_Size.htm has a rule of thumb calculator in it. enter the values (12 VDC, 8 foot run (expressed as one way circuit calculated as a round trip so double it), 16 AWG, Max Amp load (16.66) and it spits out the voltage loss. For your application, under 6% voltage loss is considered reasonable, under 3 is awesome but not totally necessary as off road lights are not a 'voltage range' critical thing. If you tinker with the values you will see that if you 'oversize' your wires, the voltage loss drops considerably, this also results in less heat, which is what you want. If you were to run two 16GA wires instead of two going to one, then that would be better. You're leaving plenty of 'room' amperage wise to be safe.
I went over the top and over engineered it, not being an electrician but being totally paranoid of knowing just enough to possibly do something wrong and fuck up my truck, I used all 14GA individual leads from the lights. In your case, two 16GA should be fine but two 14GA will lower your voltage loss and the lights will be closer to their max rated output, not a huge amount more but a little.