I've got 4 teams on levels 7 to 10 and the thing i've noticed is that every season 1 of them gets stiffed with injuries the other 3 have roughly the same no matter how for the stadium is developed. I don't spend any money on tokens on any of the teams.

I always play hard tackling with all teams because it might make a slight difference with how many cards i pick up but if i can injure an opponents best player i love it