I just put in a Tesla gen 3 charger for my neighbor and it wanted a 60 amp circuit for max charging level. Your best vet would be 60 amps or more based on this latest unit if you want future flexibility.I'm in the same situation but am considering hard wiring. My understanding is anything above 40 amps requires hard-wiring so I'm considering that route, though I would prefer plug-in. The 4xe won't take advantage of anything over 40 right now but I'm considering future capabilities and don't want to pay for the electrical installation twice. I'm looking at the Chargepoint Home Flex charger which supports up to 50 amp charging. I'm new to all this so if anyone has better info on this it would be great to hear.