I'm starting to understand what you're talking about now, Haha.
In "Sport" mode, there is no gear display...that's just the way it is, unfortunately. It's not until you actually change gears and have the car go into Selectshift mode that it will start to display them. To be honest, you'll learn in a few weeks of driving where the car shifts. Sport is almost the same as Drive...except it holds 4th for a stupid amount of time (compared to the non-existant 3rd and 4th) and doesn't go into 6th. Unless you're actually doing some 1320 passes, Sport is pretty useless. You should either use D or Selectshift.
As with engine-braking, etc...again, you should use Selectshift for that.
2013 Mustang GT - 402A GT/CS - 6R80 - Glass Roof - Engine Block Heater - SGM Exterior - CB/Miko Interior
Steeda Adjustable PHB (Street) and Steeda PH Brace, Stainless Works Retro Catback Exhaust...