While otherwise identical, multiple revisions of the board exist. Older boards that were installed in Cruis'n Exotica cabinets have a Disk ASIC JR revision A8, whereas newer boards in deluxe cabinets and all revisions of The Grid have a Disk ASIC JR revision AB. While Cruis'n Exotica appears to accept either version, The Grid must have an AB revision chip otherwise several banks of ROMs will fail to read properly. Note that it has been confirmed that swapping an A8 chip for an AB chip is possible and causes the Grid to play properly on a board previously meant for older revisions of Cruis'n Exotica.
There exists also two revisions of the PHY chip that handles firewire linking. On some boards, only one physical connection exists and the chip can only handle one link. On others, two physical connections exist and the chip can handle up to 3 links. If U8 has the text "IBMX50" on it, then it is capable of 3 links. If it has the text "IBMX51", then it is only capable of 1 link.