Is this block standard or enhanced?

Not sure what you mean by enhanced- this block has the Callaham threads, which are not as numerous as the fender block, and make the trem bar stronger and less apt to break.

What models are compatible with this block? What is the string and mount hole spacing? Callaham makes several blocks.

This model fit American made vintage style Strats, like American made 50's and 60's strats. I have an Eric Johnson signature model that it fit on. English measurements. If you have an eastern made stratocaster, you need a metric block, which they make as well. Go to the Callaham site and look at the strat blocks. They explain everything, have all the mathematical specs there. They make one for Mexican made Strats, as well. There are three blocks with appropriate dimensions for each origin of manufacture.

What is the thread size of the three mounting screws? Thanks!

It's english. Go to the callaham site. They have all of the dimensions.

does it fit on a mexican standard 06'?

They have one that fits the Mexican standard model. You have to be sure and order that block in particular. Go to the Callaham site and find it in their list of tremolo blocks.