I was doing some reading over at pro-touring.com regarding SAI. Before we go too far I will say that I am just mentioning this and don't endorse it (or the opposite). Anyway, the article was discussing what happens as the wheels are steered that's influenced by SAI and caster. It suggests that the 18.5 degree SAI of the late C4 front suspension is way too much. Part of this is evidenced by the fact that the C5 spindle has much less SAI (also C6), i.e., they fixed it for the later versions.
Chevynut, have you read that article? Any comment? I know you posted a different article about this same subject, but I don't think it expressed an ideal range or what the limit might be.
Anyway, and this is kind of lame - just calling attention to it without having my own opinion yet. Hopefully I will. We're getting into 3D geometry here and that takes more tools to analyze.