here's my 2 cents on pro BIOS flashing...
core:
mosts 9800s will hit pro (380Mhz) core speed without a problem, so you should be safe here.
memory:
if you have Infineon (3.0 ns) RAM you WILL NOT make pro stock memory speed (340 Mhz). The most you can hope for is mid 320s, maybe low 330s. This is quite strange because the memory is rated @ 333 Mhz. If you have Samsung 3.3 ns, you should be fine; if you have Samsung's 2.8 ns memory, you essentially have a pro card. Additionally pro BIOS bumps the memory voltage, so be careful about overheating, especially with Infineon chips.
o/c:
use Rage3d or RadClock to modify the boot voltage to stock non-pro speed ( 325/290 Mhz) and after the first boot start bumping the core and then memory clocks until you see artifacts, at which point you should throttle back a few percent.