There are a few points that come to mind.
Less illegal workers will likely lead to more employed Americans (who must be paid a more reasonable wage). That is good for working class Americans who would then have an easier time finding employment in those industries. But it is unavoidable that it will also raise costs a bit, which will have a mostly negative effect on the lower and middle class.
What we really need is immigration reform, not just more border security. Border security is a good thing, but does not solve the problem. If people cannot hop across the border then they will get here another way. It is not all that hard.
By immigration reform, I mean that we need to make it easier for upstanding citizens of foreign countries to immigrate to the United States legally. It should not take years, it should not cost a fortune. Those are the factors that create a situation in which people feel like they have to immigrate illegally. If those people were able to immigrate legally, they would work for normal wages and page normal taxes. In my opinion, that is good for everyone.
The last point I'll make, is that we often give large businesses (not small ones) a pass for screwing over their employees and customers. The gap between CEOs and the workers that they employ is massive these days, and they pretend that paying fair wages and paying for their employees healthcare would suddenly force them to fire people and raise wages.
No, it wouldn't. Maybe, just maybe, the guys making billions of dollars can actually afford to pay fair wages if they were not disgustingly greedy. Why would a company that is doing well enough to have multiple big-wigs making in the hundred-millions per year have to suddenly fire people in order to pay a fair wage? They wouldn't. They are just keeping all of the money instead of supporting the workers who do the grunt work.
My friend works for a company that recently got rid of their CEO (it was a board of directors type of thing), because he was doing a bad job. He got a $9 million parachute. Imagine that. You suck at your job, you cut your employees raises and eliminated their bonuses....then you get $9 million as a goodbye gift from your buddies.
Picture a bunch of rich guys sitting around a table, voting to give each other multi-million dollar bonuses for no reason at all. Then picture them claiming they'd have to fire people who are making $9 an hour if they had to pay them $10 an hour. That is what our country has become in some ways.