You seem to really understand the different aspects of an engine even if you have been a little harsh. Do you know the angle of our piston cylinders? I don't the mechanical term but what degree do our piston move up and down in the cylinder head with 90 degress being completely vertical? I would think this would have a effect on the stress on the crank and rods.
While i do agree with some of your other points i wished bmw where expolited like the B series in Honda's where. Those engines have been able to hold termendous power with just resleeving the block and boaring the oil jackets in the block etc.
For those honda lovers I had a B18 long block with the CTR head and a 5 angle value job. I ran CTR exhaust manifold because it is the best hands down. Skunk 2 exaust and cam, cam gears. also eagle rods with Enydne Pistons. This motor was a monster it outran everything! ( Oh yeah for those truely knowing their stuff it was blue printed for rpm range of 6-9k.)
Also instead of replacing the pistons how many members have increased the head gasket thickness? This could also be an intentional weak-spot so to prevent head lifting which I'm not familiar with!
Lastly building your own turbo kit will always be cheaper and better than a prefabricated kit (not sure on HP Kits and the 40,000 price though). If you know what your doing and know how to adjust the turbo specs to achieve the proper flow based on your head and powerband desire. Simply putting a T67 or whatever the biggest baddeest turbo on the market currently is, is a sign of ignorance unless you have designed your motor to utilize that turbo.