Major Drive train & Engine Layout Modification

Go out and buy the car you want. No professional would attempt what you're planning. The body sheet metal isn't shaped correctly to house a rear differential and suspension. There's no room for a drive shaft, shifter linkage, etc. Your car is going to end up with a "For Sale As Is" sign n the window.

I've had former students who were involved with drifting, and they all used front-wheel-drive cars.

My dad was "Sir". I'm not that formal and my students called me by my first name. :)

Drifting with front-wheel-drive is real easy because the front tires are pulling the car and centrifugal force pulls the back end out. You have a lot less control with rear-wheel-drive because the front tires have to be rotating to provide steering control. If you lose momentum, all you'll do is smoke the rear tires and not go anywhere.

Beyond that, I was never one to purposely wear out my tires, and my fun was on an oval asphalt race track where sliding was not desirable. Our goal was traction, not loss of traction. That's why us old-timers see drifting as a waste of time and effort.

To do what you're trying to do requires a well-equipped machine shop, all the necessary parts that will mate to each other, and LOTS of money. The only way converting a car is close to practical is when someone takes the car chassis they want and sticks a different body on it. Even that is not practical anymore because almost all cars use a unibody design. There is no frame to mount new hardware to, and cutting any part away makes the entire body very weak and unstable. The strength comes from the rolled-up sheet metal. It is much stronger than a car with a steel frame, ... Until it gets rusty, then it is weaker than a frame.

If I haven't convinced you yet to just buy what you want, look for someone else who has done what you're proposing. If you search long enough at a pile of race tracks, you might find someone who did it as a novelty, but then ask them what was involved for time and money. If you have to ask about this, I can guarantee you're going to be disappointed, and I'm hoping to save you the expense and frustration.

I'm not an expert on what you're asking or those parts. I DO have an opinion on BMWs though, but opinions can be argued. BMW, along with VW, Audi, and GM have the most customer-unfriendly business practices that cost owners lots of money. That has nothing to do with fit and finish, ride quality, reliability, etc. Rather, they design their cars to have to go back to the dealer for the expensive repairs. BMW doesn't release their paint codes to body shops, and their service information is hard to get. Their attitude is no one other than the dealer is qualified to work on cars. In reality, I found out when working for a very nice family-owned Chrysler dealership, it's the independent mechanics that have reached the pinnacle of success. They have to relearn every new brand, model, and system every year with no help from the manufacturers.

The closest I can come to a valid recommendation is to take your time, and check out what the other guys are using. Ask them a bunch of questions and for their advice. When I was running in the "amateur" class in the '70s and '80s, the older guys loved talking about their stuff, and they really loved when people asked them about it. Even if you don't agree with their advice, you'll make a pile of new friends.

I understand your comment about respecting us "older" guys too, and thank you. I felt the same way toward my bosses and always called them "Mr.... ", But once I started teaching, I preferred to be called by my first name. Part of that is because two of my best friends are my former instructors, and it feels weird now to call them by their first name. I just did an old car show swap meet last week and as usual, I got visited by a half dozen of my former students. They were young adults in a technical college when we met, and since I'm fighting getting older, once my students catch up to me, I don't want them calling me "Mr."

Anyway, with the respect you've shown, I can pretty much tell you're going to have fun and you'll attract new friends easily. Once you become one of the experts, be sure to help the new guys. Come back when you have technical questions I can help with. My specialties are Electrical, Suspension and Alignment, and Brakes, but as they pertain to daily-driver cars and trucks. I don't know if I can apply that knowledge to drifting.