hmmm well, you can do a 400Mhz rise on the bus. But understand the basic fundamentals of Pentium 4 2.0Ghz.

1.its a 478 pin socket
2.its 130nm architecture which spells for a lot of heatttt!
3.the multiplier is 20* which is obviously the reason why u wont be OC that much.
4.Your consolation would be that of Northwood. they have legendary ocers under that name..

i think u would have to get excellent cooling first if u r attempting to overclocking this proc.