How do i beat the elite 4 in pokemon diamond without having to level up my pokemon?

you really need to make time to level your pokemon or you will bot have a chance of beating them. this comes from a long time pokemon fan so you will need to make time to train then , but if you really want to buy an AR and do it that way, but that really takes the fun out of the game though. and as for the gts i dont think you can use that befor you beat the elite four the first time.