Thanks very much for the replies.
I think I will stick to the 550W as I'll most probably upgrade my components again later in the year and will keep the PSU. You could well be right in regard to not needing any intakes if I'm just using one harddrive - by the way, no idea why I say Seagate when I actually meant to say Hitachi Deskstar
Any idea if the Ninja would fit the Asus P5WDG2-WS Professional board?
Where?wolf can I ask what cpu you are running, if it is overclocked and what your load temps are with just the one exhaust. Good idea about the duct - may knock one up out of plexi.
Does the Antec Solo case still come with those rubber band type HD holder straps?
I'm running a AMD64 3000+ @ 400MHz undervolted to 1.48V.
I have max load 50C after 1 1/2 hour 19.3 C room temp.
My duct is embracing the distance between the fan and the edge of the heatsink fins on 4 sides. Then on 3 sides on the sink itself. Make sure the duct fits snugly to the sides of the Ninja. I have about 1 1/2 cm gap between the top of the Ninja and the duct.
Also make sure, to "softmount" the case fan(s) with some elastic straps. Dont use screws! They transfer the vibrations from the fan to the case. And before you mount anything into the case. Remove the stamped fan grilles in front of the fans. Will reduce noise and improve airflow. If you have pets or children? Then you may wanna get get a finger guard, made out of rounded wire instead for the exhaust. Such a rounded wire guard, makes less noise and does'nt hinder the airflow as much as the stamped ones.
If you want to make the edge on the fan holes look better after the cutting? Get some "U" shaped door, or window isolation. And glue this to the edge.
Just make sure you stretch it enough, so it wont get in contact with the fan blades. Also clean the case throughout after the cutting.
Tip for 92 mm intake for the Solo case (If you feel you need one)? Get a Nexus 92mm or a Akasa amber series fan. Those are quiet for beeing a 92mm fan. Unfortunatly, Noctua, have'nt started to sell any 92mm fan separatly yet. At least to my knowlege.
Just for the sake of it. As I guess your cpu may eventually run slightly more hot than mine. I mounted a 1200 rpm ( in reality, is this fan 1250 rpm) Noctua on the Ninja (Still ducted to the exhaust fan). Then I connected the U.L.N.A. resistor that comes with the Noctua fan. This will take it down to about 640 rpm. and about 30CFM, 19DbA noise, (according to SPCR measure). This as the U.L.N.A. will cut the speed down to half). So it's vely, vely quiet, as Elmer Fudd would have said.
And at this point. I cant hear the fan at at all, sitting in front of the pc . Not even if I open the case door I cant distinguish it from the other 2 Noctua fans at 840 rpm. And the Nexus fan on my videocard at low rpm. I'm about 50 cm away from the case then. I live in the countryside. So it's a very quiet enviromment.
This addition of the low rpm Noctua, gave 31C idle and 47C load
Case temp 30 idle 33 load
Today when testing. I had 19.8 C room temp