I'm looking at building a new IT car that is perfect in almost every way, but most of the wiring has all been fried/damaged. Rather than moving all wiring from another car, can I leave the stock wiring in place but run everything through a "painless wiring" kit and still be legal?

I see no performance advantage to going this way (just a huge time/expense saver), but I figured I'd check before going down this path.