Well, i think the best thing to go to limits is to do safety trainings. I've done some. Don't know if these are offfered in the US. This is a little video from 2009 at the Nürburgring safety training centre.

Over here in germany we have some Autobahn parts with no speed limits. Fastest i drove with my N/A was around 158 mph and with other more powerful cars around 190 mph (in early morning hours with no traffic).