only if using a device that requires it.is there a cable for the pcle too?
most low end graphics cards run off the PCIe slot alone with no need for 8pin PCIe power cables.
any decent case will fit any standard ATX power supply.If i could upgrade the casing, could I install that be quite psu that I found earlier?
this would definitely be the best option.
you would also see better temperatures and more options in regards to future upgrades or additions with a much nicer case than that OEM thing.