Don't quote me,but this is off the top of my head....
2nd gear max speed - 69 mph
3rd gear max speed - 104 mph
Of course,this speed is at redline,so I like to shift down about 15-20mph below speed above.
If you are at 70mph,shift to 3rd and you'll be in the powerband. I shift to 2nd if under 60mph,anything above,I hit 3rd.
Stick with the "40-60-80" rule when downshifting....these are safe and good max mph's to downshift into in those gears respectively for 1st,2nd,3rd. Should put you around 5k rpm's at those speed in the appropriate gear.