yes, you can flash an r350 core from pro to xt
youll gain about 5-15 fps in bf2, and a higher setting or two.
theres only one problem
something that is unlocked by the bios flash is slightly corrupted, to me it doesnt matter because all it translates to in bf2 are blocky shadows at point blank range (no shading, just black or the other color, no big deal)
on the desktop i get slight graphics distortion from something or other, but that could be the late after effects of a water leak in my water cooling system.
if you dont mind minor stuff you can get the bios for the flash from here;
they say not to flash the r350 core, i did it anyway, as any person with little money and a high degree of needs in the way of performance would.
its a crapshoot, and be sure to get rid of that stock heatsink, go with a zalman vf-700(?) think thats what its called, or a swiftech mcp60 waterblock if you are W/Cing.
hope this helps
also, might i suggest backing up your original bios, pre-ocing to 412 core and 365 mem, making sure its stable, and having a pci graphics card as a back up in case? you should do all this anyway, but its esp. true for this card, and be sure to uninstall drivers first