Is the only difference between a base Ultra and an equivalently spec'd Max the front Thunderbolt 4 ports versus the front USB-C ports? Or does upgrading to the Ultra processor substitute Thunderbolt 4 ports in place of the USB-C ports?
It looks like when you upgrade the Max to Ultra in the configurator, the front panel ports in the summary switch from USB-C to Thunderbolt 4. Interestingly, the shipment date is shown as late March if you go that route (but if you actually place the order, it'll switch to May - I tried it thinking it might be an option to get it sooner but cancelled when the correct date of May delivery appeared).