Very interesting analysis about the effects of installing lowering springs.
I have a suggestion that will give your theory a little more factual 'weight'...
Your calculations should factor in the progressive spring rate
of every aftermarket lowering spring on the market.
The current crop of lowering spring for the M3 will all have different progressive spring rates, so they will all behave a little different with the OE shocks and struts.
From my perspective, Dinan and Eibach got it right...and everyone else got it wrong.