I agree with Plymouth 65, you're gonna have a hard time wrangling the front end of that thing with a 440 in it, even with aluminum parts. For the same amount of money for big block A body headers and all the other conversion parts you'll need, you'll come pretty close to the cost of a nice 408 stroker rotating assembly. 360 Magnum engines can be found for a couple hundred bucks, and if you really are going all out then aluminum heads and parts on a small block will really lighten up the front end.
If you're going for M3 performance then weight and stiffness is going to be the name of your game. US CarTool makes excellent chassis stiffening products, and you might even want to consider a half cage or something similar to stiffen up the chassis. FWIW, I own an A body and I've ridden in my roomate's '09 M3! It would take a pretty penny to make them comparable on a racetrack with a competent driver.
I am not saying what you are trying to achieve is impossible. What I am saying is I would highly suggest planning your build for your end results, not hyper-focusing on what the most expensive or most badass parts are. Nice suspension parts won't do their job correctly if the chassis is as stiff as a wet noodle. A big engine will get you lots of power, but that won't matter if you're trying to retain speed through corners.
And a good 'ol Uncle Tony's Garage video about weight. This applies for cornering too! Making a car lighter doesn't just affect its straightline performance:
I sincerely wish you the best of luck with this build, I am not trying to tear it down. I myself want to build a good-handling, trackday A-body but I don't have the budget or space for that yet. You asked for our opinions, and this is mine. Good luck sir! I'm excited to see this build progress.
