use the wirng harness form your can is fine you will have to cut and strech some of the wires. yes it works fine i have done this swap in my civic 2 times now and i just put a gsr in it a few weeks ago and i am still using a dx wiring harness. also you will need the rear Vtec delsol mount. if your ls is has the starter and all that than you will not need to buy it; however if your ls does not have these things you will need them also..... it has been about 5 years sence i did the first swap so i may be forgeting some stuff.