I wonder if the part where you switched the fan to intake really helped the temps. Did you try swapping directions to see which performed better?
I was always under the impression that if you can only have one fan, point it out. get that heat out
When I first got the PC, I tried both ways, and the fan as an intake cooled the system better. I had it as exhaust, ran the PC at 100% CPU utilization for a few hours, checked the temps through Via's hardware monitoring software, reversed the fan, ran 100% CPU util for a few more hours, and then checked the temps again. As intake, the temps were ~10F lower.
This maybe due to the layout of the SV24/25. The PSU of the SV24/25 is mounted in the FRONT of the case with the exhaust actually blowing hot air into the case. IMO, not exactly the best layout. Apparently, Shuttle agreed, as the layout of the case is different for their newer SFF PCs. The PSU is in the back exhausting hot air out of the case as "normal" cases do. If the PSU was exhausting hot air out the back, and I had the (rear) case fan as an intake, it'd probably just suck the hot air right back in.
Over the weekend, I added an ATI Radeon 7000 PCI and tried the fan as intake and exhaust, it now seems to work better as exhaust. The PCI cards in the SV24/25 fit into a riser slot and it restricts airflow a bit by sectioning off part of the case. Overall, temps are much higher now. I've also noticed that as exhaust, the Vantec fan is louder than as an intake.
One thing I plan to do to help keep the system cool is to cut a hole in the side of the case where the PSU exhaust is, and either make a small exhaust duct or put in a small, slow 5V fan to help exhaust the hot air.
I may also try to run the PSU fan at 5V or 7V, but I don't know if I want to cut open the PSU.