CPW (Current Performance Wiring) made mine. It was nicely done, although when tuning it with the Holley dominator it did have some trouble registering it. I've never been convinced it's a good idea to extend the wiring - unless you stuck the fuse box at the very rear of the car, there should be ample wire once you pull it out of the harness ... all 3 times i've used the gmpp harness i've had excess loop tucked away