300 watt psu fits with the SD32G2 Mobo as the ram is in the front behind the faceplate and under the drive cage like the traditional G, G2s and some G5s (unlike the SN95G5 and ST20G5). I believe the back mod is only for those models with the ram under the PSU, right?
And according to Shuttle:SD32G2 Compatibility List
As to the faceplate, I had to use the Power/Reset flat cable from a G series faceplate due to it's extra length. But I do believe the connector on the Conroe board must be in a closer spot, though, making it pretty much the same, no? And the front port bracket might have to be switched with the SN95 one. I say might because I don't know the size of yours. I had to mod the aluminum bit of my port bracket so it didn't stick out so much. Other than that, the faceplate snaps right in.