where you find those stats?
In your team overview, the "Team Stats" link.
Yes, I think they have good defense in compare with other teams in my league.
I have some guards with decent outside defense but crap inside defense that foul quite a bit, but I can't say that's the issue. We're all still trying to figure out why some players tend to foul more than others, so I'm more or less throwing ideas out there to see if any of them work.
Stamina is problem maybe, i don´t look at it...but I´m not sure I have so worse stamina level in my players.
What level of stamina is good to have?
This is debatable. I want at least respectable on all my players. That isn't to say I have attained this, as my team ranges from atrocious to proficient. There's a bit of give-and-take with stamina, as the weeks you spend training stamina are weeks you aren't spending training your trainees in a main skill.