You need to be Dark(from using dark chips) or be in Dark Cross. I wouldn't recomend using dark chips because they permanently remove on hp from your max everytime you use one.
Heard that MMBN5: Double Team had voice overs. Been think about geting it. As for DSChips... DSChips will only work when MegaMan is in a darkend state. By using a DarkChip, Mega Man will be able to use certain chips such as DS chips and some others, like DarkLine or Static. However, he won't be able to use chips such as the Gun Del Sol, or SP Chips. So it comes down to wether you like Light or Dark. Dark also carries the effect of losing 1Hp ever time DarkChips are use in battle, and the like. Dark also does have some good things, though. Like being able to use the BugCharge Giga Chip, and the Black Wing Mega Chip. Being Light also have good points like Using the powers of the Sanctuary Mega Chip, and some others. I seem to remember some others, but I think that was for BN4 or something. Well hope that helped a bit. ^_^
Dark Chips.......EVIL!!!!!! Well....Pretty much. I mean thet do have "Dark" in it. Oh yeah, here's a little tidbit of info...Did you know you can become good again even after using a Dark Chip?? Yes, it is possible!!! How? Well, you all you have to do is- *shot*