My experience with algae is that if you don't expose your coolant to light you won't get any.
You will definitely need to mass-load the side panels. There's some loading already there, but not nearly enough to deal with pump vibration.
Those silicone grommets are great for isolating drives, but that gel stuff at Petras is at least an order of magnitude more effective. Spend the four bucks.
The bright side about that case is that the vents around the outside of the front hatch seem to reduce the airflow "whoosh" noise.
Any of those pumps will cool your gear. If you were pushing for a max overclock, then, yeah, higher pressure will drop your temps a couple of degrees, which might translate to a bit more O/C - once you've raised voltages yet again.
It's a trade-off. Like most everything else. If you were trying to as-quiet-as-possible, I'd be pointing you at the innovatek/eheim HPPS pump, which is dead silent (but vibrates as all Eheims seem to do) but is also weak-ass and your temps will be higher.
BTW, I have read that the 350s with modded tops at petras are both quieter and have a bit more flow than stock. I've no personal experience with these (maybe next build) but it sounds like something worth checking out.
As far as the 160 goes - don't think so much about cubic capacity as frontal area when comparing radiators, then think fin pitch. There are some other 'HA' series rads. And I'm pretty sure you can get 'em directly from thermochill.co.uk.
Have a look at
this thread (note that Marci owns Thermochill - but he's an enthusiast.
Personally, I've always liked that square form factor - much easier to put it in the lower front of a tower case. Not sure it that'll work for your case, though...