North American Galant to World market Galant VR4 conversion?

I am trying to make my run of the mill NA 2000 model yr. Galant look like a World Market 2000 model yr. Galant VR4. almost all of the work is
swap in - swap out with no modifications, I have just about all the body pieces and I have ran into a problem with the headlights . the Japanese oem headlamps fit with no mods, but How do I convert a NA spec wiring harness so the lights work properly or do I have to buy a Japanese spec wiring harness to make it work?
The US spec harness is H4 and it handles (low beam/ High beam)
The Jap spec harness is H1 for low beam and H7 for high beam.
I also read somewhere that if I change the bulbs to HID that the US spec harness will work because its just a plug and play item. Is this true? If I have the Jap oem headlights and just switch the bulbs I can use the US spec harness?
I have the V6 with an automatic tranny are there any easy things I can do to increase the Horse Power and not reduce the reliability of the power tran?
Thanks in Advance, Emails welcome on this subject, or I can always come back here.
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