Each V3 cabinet is capable of receiving 350 kW AC input from the grid and another 575 kW DC input from its neighboring cabinets (up to 7 cabinets can share with one another), battery storage, and/or solar.
A single cabinet, 4 stall installation with no solar or battery storage would max out at 87.5 kW per car if the site was full. A two cabinet, 8 stall installation with no solar or battery storage would also max out at 87.5 kW per car if the site was full. These numbers increase with solar and/or battery storage depending on how much is available.
Many sites, despite having enough cabinet capacity, are limited by the transformer that feeds the site. I've seen 8 stall V3s on a 500 kVA transformer, which would effectively restrict vehicles to 62.5 kW each if the site was full.
Of course, as vehicles approach full and ramp down their charge rates, more power becomes available for other vehicles. So in practice, it's rate for users of V3 sites to experience throttling and that will become even less frequent as Tesla adds solar and/or batteries to busy sites. Since V3 sites share power between cabinets, users really don't have to think about where they plug in, since power can be directed anywhere. Gone are the days of A-B pairing, which is great.