"The incarceration rate for native-born men in the 18-39 age group was five times higher than for foreign-born men in the same age group."

KK, in no way does that say anything for certain about illegal immigrants, since your numbers are refering to immigrants in general. Also how many illegal aliens arrested are simply deported? This too, could lower the rates.

I have no idea about the real rates, only that what you posted does not prove anything. My gut feeling is that when we are talking about illegals from the south we can draw some general conclusons. Simply by looking at what drives them to come here, you can assume certian things are true. If they were highly educated, they would most likely not have the same drive to come here illegally. If they came from wealthy back grounds they most likely would not be here. If they had established homes with children they would be less likely to come across the border. If they were adverse to risk taking, they most likely would not be here.
So, if you take any population of young, lower educated and from lower income families, take them away from their established roots and put them in an enviroment with other young men like them, make rules that make it had to get established long term, and give them more money then they are used to, isn't it reasonable to assume that they would be at higher risk to commit certian crimes than the general population of similar aged men. While they may be lower in drug or theft crimes, they most likely would be higher in sex crimes, DWI, and crimes of passion.
I have no statistics to back it up, but common sense tells me it most likely is true of all young men, regardless of race or ethinicty.