Does anybody see a connection between illegal immigrants and decreased productivity of the U.S.?

My personal view on the subject is that immigration has gotten out of hand and the biggest difference that I can see (at least in the cities) is that immigrants today utilize US markets for profit and export that profit out of our country, whilst immigrants of old came here and stayed here and spent their profits here. Just looking for any views on the subject. Thanks.

This is a very simplistic view of how immigration works and the effects it has on the US.
For many years and even today immigration builds this country. The fact that some send money home is insignificant because very few ever make enough that they can afford to send more than they earn and most never earn enough to send any at all. Some will live in bad conditions, but most won’t.’

If you want a fascinating look into immigration read the History of Immigration Through the 1850s, http://www.crfforum.org/topics/?topicid=35&catid=8&view=document&id=74

It might just change how you look at immigration in the US.