PSU modifying on a Shuttle SS51G

Well I got a Shuttle SS51G, one of those mini pc thingies. And I want silent operation on it.

(you can read more about the SS51G in this THG review http://www.tomshardware.com/howto/20020815/index.html)

Specs.

P4 2400
Radeon 9500Pro
DDR333 512Mb
HD 60Gb Seagate Barracuda 7200rpm
LG Electronics GCC-4320BB DVD+CDRW Combo

So far I have thrown out the original CPU fan and replaced it with a 20dBA Zalman (I have a 12dBA papst on the way). I have also put a Zalman ZM80-HP on my Radeon 9500 pro so it doesn’t make a sound, it’s the heatpipe thing.

Now I have come to the PSU, and as I see it I have 3 options.

The psu is a Achme 200W with active PFC.

1.Replacing the PSU fan with a Papst Fan that has a noise lvl of about 18dBA, the problem is I don’t know if it will put through all the air the PSU needs. Also with I being an active PFC I don’t know how it will run with a different fan.

2.I replace the entire Flex ATX PSU with one that has a more silent operation. The only one I found that fit (that I know will be more silent), was a seasonic SS-135NP, but I only puts out 135watt, which won’t be enough.

3.Use a external PSU while the computer is stationary in my home and just switch back to the original if I am of to a lan or something. here I have a few choises. Either the Zalman ZM300A-APF 300W or a Nexus NX-3000 300W, both will have a noise lvl around 25dBA at the max load I will be able to put on them.

4.Or I could go with a smaller Micro ATX seasonic SS-200SFC 200W (or something similar) and try to mod it into the chassi. The problem with the seasonic, it think, is that I would probably put a heavy load on it and it would make the fan run at a high rpm and don’t make it that much more quite then the one I have now.

So what do you guys think I should do? some advise would be great.
Also does anyone know if there is some kind of software that can calculate/estimate the number of watt the computer is pulling out of the PSU?