Our economy does well by carrying out economic activity. You can't remove a huge chunk of people who are active in the economy and expect it to do better. It makes absolutely no sense.
It is a myth that illegal immigrants are a huge drain on our country. Don't believe it than offer up some evidence. They help keep a number of goods and services at low prices, They contribute through general economic activity, and by paying sales and property taxes.
It seems pretty clear that businesses can and will move to cheaper labor markets. There is no reason to expect that businesses that lose a cheap labor source, will fill those positions by paying a higher wage to Americans, rather than moving or finding an alternative cheap labor source. And if they do that extra cost will simply be passed on to the consumer for no net affect.
We need to generate legitimate work opportunities for Americans. Not chase out illegals so that our college grads can flip burgers.