Do i need to return to stock first?

[dew1520]

Rite now i'm running the diablo 93 cai performance tune, however i just got a cmr custom tune. My question is, do i need to return the car to stock first, then install the cmr custom tune? Or cam i just install the cmr custom tune without returning it back to stop first? Also i read somewhere once you do go back to stock, it will erase your cmr custom tune and you have to send/install it back to your predator.

[mikel]

Just load the tune and go...