1) 160-170 is a HUGE range. Really, this is the difference between schools ranked in the Top 10 and around 50ish. University of Florida is not the same as UMichigan.
I would recommend spending some time messing with http://www.lawschoolpredictor.com/wp-content/uploads/Law-School-Predictor-Full-Time-Programs.htm
as well as
This is where the predictor grabs its data fyi.
All that said,
If you end up with a 3.0 and a 160, you are in okay shape for schools ranked between 50-100 and in good shape for schools outside the top 100. If you end up with a 170, you are looking at Top 50 schools.
Note on ranking
Don't get worried about its hype. The reality is the strong majority of schools outside of the Top20 have pretty similar employment figures. Between T14 and T100, there are surely differences, but no the same as T6 v. sub-T100 schools. In other words, for the schools you would be considering, ranking plays a relatively small role in your end career. The big factor that will drive your employment (and, lets face it, that is the whole point for law school) out of these schools will be the particular school's regional pull. Therefore, apply to as many schools in the region you hope to live and work in after law school.