Running any binary that you can't examine the source of (and confirm it was built from it without modification) is risky. It's mostly a balance of trust and risk. Even developers have been known to insert what we could malware.
That said, if you get your cracked content from a trusted source, I'd say it's generally safe. Otherwise, exercise extreme caution.
Is GMG an official reseller? Maybe I am out of the loop, but I thought they operated in the grey market.