I'll give you retail price, because I don't pay retail. My Pinarello is set up just like your
Specialized, with flat mount brakes front and rear. I wanted XTR levers, which meant switching to LV oil.
M9200 XTR XC levers $230
M9200 XTR post mount front caliper with metallic pads $170
TRP post mount adapter $16.00
BR-MT805 flat mount rear caliper with metallic pads $115.00
(2) BH90 hose kits $80
(2) RT-CL900 Dura-Ace 160mm rotors $200
Shimano 1L low viscosity oil $80, but you only would need 100ml-200ml if you're careful ($19 each or $55 for 500ml)
Total overkill, yes, but I wanted the XTR levers.