ghettochild8587

I have an auto 90 240sx and a 89 240sx 5 speed. Some one is giving me a 95 KA24DE. I'm looking for the simplest ,most cost effective way to put it in. Will it bolt up to the stock trans to either ,if not will the 95 KA24DE with trans bolt up to the drive shaft. I'm guessing the wire harness needs to me putted and replaced ,is this true. Is there alot of custom work needed to be done. How much do you think on average a mechanic would charge for such an installation