What is the max % that IRS can garnish from your wages?

Since the IRS doesn't follow or obey the law it would depend on what you owe them, how long you have owe them, and if you try to avoid paying them.

I disagree. The IRS does in fact obey the laws associated with garnishment limitations.

There HAVE been abuses in the past, but when the courts found out about them, they were deal with rather harshly (in one case, a large tax debt was completely forgiven because of the associated abuse).