It took about two days to completely rewire the Jeep. Most of that time was spent under the dash. The engine harness was pretty easy, but the headlight harness (PN 38225) was a piece of cake. We had to remove the headlights, grille, and radiator overflow, but everything about the headlight harness was plug-and-play with zero crimping or modifications necessary. Z&M sent us its rear lamp harnesses (PN 39461 and PN 39551), but after inspecting our stock harness we sent them back since our factory wiring was uncharacteristically (for an old Jeep) unmolested.