If you are referring to the speedo/tach instrument cluster it has LEDs, not incandescent, but I understand the worry about ruining the one you have. As for the mileage, I can't say for certain but i feel like the mileage would be saved on the car's computer and not the cluster.
For my 05, all the bulbs in the HVAC panel (display and control buttons) were incandescent, just different sizes.
One observation when switching to LEDs is that the LEDs you find are most likely going to be on a spacer or riser that allows room for the resistor, add that to the fact that LEDs...
Have you checked your fuses as well? I am starting to think maybe there is some sort of separate controller for the screen if that is the only thing working for you and also the only thing not working for me. I tried to jiggle the plug and wires in the back but did not seem to do anything, was...
I had this same issue so I decided to do the whole LED swap, but now my problem is the entire display wont light up. I know the bulbs are fine as i tested them to an outside source and got them to light up and i flipped the bulbs around several times thinking i was not getting the polarity...