Hi Salman, a UZ or JZ swap in an E46 is perfectly doable but I advise doing a ton and then some more research before you embark on any project. Google is your friend. There's a lot you can learn beforehand to avoid expensive headaches down the road. I have done a couple of similar swaps myself and since I wanted to do as much work as I could myself, I read all about the transmission and gearing required to work with these engines, what you need to get set up and running in terms of electronics, cooling system, etc. As far as technically sound mechanics are concerned, there's probably nobody better than Nomi or his brother whose name I can't recall. Both of them have superb fabrication skills. They don't cut corners and are well worth the money they charge. I speak for Karachi though...