1) Leave the S-Video input active when the selected source is DVI or Component.
2) Have a surround setting for Dolby Digital 2/0 so that the unit will stay in either Dolby 5.1 or 2.0 as the input switches and will not go off to prologic. This is an issue with HD-TV inputs when every channel has a different format and the unit keep overriding your selection. This would allow the 990 to be compatiable with the 950 in this regard.