what about the idea of flipping the exhaust manifold and cutting it off so you just have to make a couple pipe modifications. an exhaust shop should be able to do that for you. or a good place to visit is any diesel performance shop, they should be able to make you somthing.
I have considered the idea of flipping & chopping the stock manifold, but i doubt it can handle the heat. It would probably crack. What you really want is a custom one fabbed from Inconel (if you have $$$), or some heavier gage stainless, like 316L or the like.
Like it has been said above, crap in, crap out. Half-assing a turbo job on an already strung out motor like the M42 will probably leave your pistons full of holes and lots of coolant in your oil. I would LOVE to see a turbo E30 M42 in the US, or in the hands of one of our members. Let's all go win the lottery and do it!
Here was something I started a loooooong time ago, on the mostly M20-lovers' forum.
http://forums.bimmerforums.com/forum/showthread.php?t=141081Although I rapidly realized that I did not have the $ or time to do this right, the thread became a somewhat useful knowledge base.
I recommend something similar here. Perhaps if we all talk & build up a good base of knowledge and maybe soemthing like a well-organized list of parts I will sticky a DIY M42 Turbo thread in here or the DIY section. I guess if it is all theoretical it will be in here. Once someone does it I will put one in the DIY section.
Actually, I just decided to start a new thread in here for this. It should be within all of your capacities to find it in this MONSTER discussion board :p .