PS I clicked on the Sas-tec link and I noticed that it has expanded and contains more information than your earlier post on the teiz blog. There are now impact measurements for the exact pieces of armor that are used in the jacket. This is very interesting. (I don't understand the color codes on the product images, but I'm guessing these were copy/pasted from some other catalogue and can be ignored.)
I notice that level 2 vs level 1 for the back protector requires halving the residual impact force. I don't quite know what that means in medical terms, but it seems very meaningful and well worth a few extra $$. (Personally I'd be happy to pay for an optional upgrade to full level-2 everywhere.)
Thanks for making this information easy to find.