This is a strange comparison because both the X5 and the GLE 63 Coupe have been tuned by Pits. The 11-minute video showcasing the two SUVs ends with a race between the two. After tuning, the X5 M has 650 HP under the hood, and the GLE 63 Coupe went from 557 HP up to 700 HP. So the GLE has some more power, but still, the both of them are beastly SUVs.
Well worth the watch, oh, and its in Greek but has English subtitles.