I have a 301 and I just received the 184 update. So far the only difference I noticed is the Point Dish / Signal Strenght screen. It has 7 Satellites listed (61.5, 105, 110, 119, 121, 129, 148) on the left, and a new (I think it's new) "Peak Angles" menu on the right. Only one strength bar at the bottom of the screen. The Peak Angles menu allows you to select Dish 300, Dish 500, or SuperDish and gives the recommended angles for dish positioning. However, when you select Superdish, "N/A" is listed in all the angles except for 105 and 121. Weird.
The Check Switch menu off the main screen now has a check box for "SuperDish /129". I have not attempted this test, as I don't have a SuperDish.
Anyway, hope this fill you're appetite for useless information ont he 301 for now.
Kurt