Scud Race used the DSB1 sound hardware. I do have a DSB2 from a Sega Rally 2 cab but I swapped it with Daytona 2 ROMs; however when I track down SpikeOut, I myself would be after another DSB2. @tsangpopohk - IDK if this site ships to Hong Kong, but I have seen fairly priced DSB2 boards on Coin-Op Parts Etc. They're in Connecticut USA. Some of the items they sell are used and sold AS-IS, but the Scud Race DSB1 I bought from there does work; I just needed to clean it and dust it off as it was playing scratchy music at first. To swap the ROMs out I recommend you grab a Jonard chip puller as a flathead screwdriver can bend the legs on the chips.