Sue or not, what you suggest is flat out illegal, and you will harm your customers when the genuine installer runs. It is shortcuts like this that screw people out of a good PC experience in the long run.
what you are doing is illegal. Especially if you are charging them money and telling them they are getting the real deal. If your customer find out they wouldn't be happy and could sue you. So could Microsoft.
Your business would fail utterly in the long run if you supplied your customers with bootlegged products. There are large legal and ethical ramifications in your business model. You should revise it.