21:49; Elite Four Rematch - Challenge Mode
Elite Four Member (Ghost-type): Cofagrigus Lv. 77, Gengar Lv. 77, Froslass Lv. 77, Drifblim Lv. 77, Golurk Lv. 77, Chandelure Lv. 79
Elite Four Member (Dark-type); Tyranitar Lv. 77, Houndoom Lv. 77, Scrafty Lv. 77, Honchkrow Lv. 77, Krookodile Lv. 77, Bisharp Lv. 79
Elite Four Member (Psychic-type); Musharna Lv. 77, Alakazam Lv. 77, Reuniclus Lv. 77, Gothitelle Lv. 77, Gallade Lv. 77, Metagross Lv. 79
Elite Four Member (Fighting-type); Throh Lv. 77, Sawk Lv. 77, Mienshao Lv. 77, Machamp Lv. 77, Lucario Lv. 77, Conkeldurr Lv. 79<
From Serebii. So for the most part they have very different teams meaning Challenge Mode not only ups levels but also changes some Pokemon, which is awesome. Does this mean Challenge Mode only applies to postgame stuff? I hope not, and I don't think this is necessarily proof that it does since E4 postgame rematches always include Pokes not in the regional dex.
EDIT: Iris replaces her Druddigon with a Salamence. Her Haxorus is now Level 83, everything else is Level 81. This makes her the first ever Champion to be stronger in levels than GSC Red!