NRG Parking Question

Hoping some Houston locals can help me out. I'm looking at options for parking this weekend for Beyonce, and right now the 2 best options seem to be:

– Buy a parking spot online from one of the unofficial lots/garages (aka 1500 Old Spanish Trail garage) for around $50/60 (official lots resale at like $150 right now lol not doing that)
– Park at the Fannin South center for $25 and take the metro the 1 stop up to the stadium

So my questions:

1. Are those unofficial lots legit? Any risk of being scammed? (They're being sold on AXS)

2. How packed with the Fannin South lot get? And will it be better for getting out at the end of the night like I think it will?