For anything official, you will need to flash back to stock. It appears that sprint updates will from now on do a preliminary check to see if all their crapware is installed. It is highly recommended though if you are running a di07 based rom to update it to di18 radio before flashing a di18 rom. There are di18 updates on xda for non-stock roms (removes this preliminary check but flashes radio and other goodies)
yeah, I was referring to custom ROMs... if I am willing to wait a couple of days after an official update comes out, you're saying I can flash a custom ROM that contains both the baseband update (radio) and the ROM without the verification obviously? I don't see any need to go back to stock at this point...