to the original poster: You have a 2004, it has the tremec... definately go with 4.10's
You have to remember that a lot of people freaking out about 4.10s have a 2001 or lower which has the other tranny. For the most part those are the people that are considering 3.73's BUT 3.73's on an early 01 are pretty much equal to 4.10's on an 04 as far as RPM's are concerned.
With 4.10's at 70 you should be right around 2330 RPM which isn't bad at all.