Yes. If yu beat them 1ce, they get Level 65-80 strong
After defeating the Elite Four once, their Pokemon are much stronger than before, and with new Pokemon. There is no new Elite Four to battle, though.
lance
beat elite four rematch
They don't get sronger, but your Pokemon will get stronger if you battle them a lot.
The elite four
Beat the Elite four and the Champion.
A lv:100 venusuar!!
Legendaries or Feraligatr, Ampharos, and Heracross.
You have to get an action replay and battle one of the elite four
Lv 42 to lv 45
you have to beat the elite 4 89 times
get stronger then you are before