it's possible to make this case extremely quiet, but it takes some work.
the main problem is airflow and the psu fan, what i did was remove half of the psu casing(a few screws and it pops right off)- this allowed me to change the fan easily, soft mount it and more importantly, expose about 20% of the fan to free airflow. like this:
i also reversed the fan to blow into the case, mainly because my cpu hs is bare, but i expect it to have a favourable effect on the psu and components in the vicinity like you vrms. leaving the pci slots open will free up the airflow significantly, though you may have to consider some ducting so the cool air is correctly utilised.
i can't guarantee this will be enough, but it will definitely be magnitudes better than the stock setup.
unless you are doing some light gaming or need 3+ monitors i can't see the advantage of getting a 5450.
the mounting holes for the hdds are for 3.5" drives, i drilled a hole in order to screw my ssd right in.
i expect the stock hs to be pretty quiet at idle but very loud during load so keep that in mind. fan longevity and sound quality also seem to be considerable issues.
the cabling is a minor issue, there aren't many and they're very short, some anchors and cable ties will let you put them aside wherever you please.
if you're not going to use the drive tray for anything other than the ssd, consider removing it entirely. if i didn't have an odd installed, i could fit my hypertx in there, a 92mm tower hs- but note that this depends entirely on the cpu position on the mb. the ssd can be mounted virtually anywhere.