Replacing PVC kitchen doors with maple/MDF

Hi all, Our builder offers standard kitchen oak cabinet doors in various stains or choice of painted PVC. I'm thinking of taking the standard white painted PVC doors (nice looking shaker style but wouldn't count on them for longevity) and replacing them with high quality white MDF or painted maple? I'm guessing the inside of the cabinets are the same regardless or would I have to replace the whole cabinet, inside and door front?. The builder is offering 8k to upgrade the cabinet doors and although it's a nice sized kitchen, it's not that huge (16'x10' L shaped).

Any input would be appreciated.