biggest difference between SE and regular/PRO is the 64 bit bus(se) vs. 128 bit bus(reg/pro). Framewhores will complain greatly about this, but they think everyone else is a Framewhore also and thus try and educate them on the "failing".
Will it perform like a 9600 Pro? No
Will it be leaps and bounds above what you have right now? Probably, if you have anything lower than a GF3 anyway.(what do you have right now anyway?)
Compare the specs of your current GPU and the specs of the 9600 series
as seen here. If everything(clockspeed, amt of RAM, ect) is better than what you have now, and it fits your budget and computer(sounds like you need a new case to be honest), then go for it.