I softmodded a Powercolor 9800SE to 8 pipes but I have to underclock it to 335 mhz so I dont get artifacts. This would be the worst you can expect to happen with a softmod 9800se(it must have 256 bit memory) with a VGA silencer. Still it's only a few fps behind a 9800 XT in any game.
Brand doesnt really matter with the 9800SE cards, but they MUST have 256 bit memory if you want to softmod.
9800se softmodded would be the best bandforbuck, but im not sure on the success rate, a lot of cards might not be able to work with all pipelines enabled
a 256bit 9800se costs about $150 mabe a little less, so its sorta a tossup as a real 9800pro is only $180, and you can always try to grab one that will flash into a 9800xt