ok, the 10k mod is a 10k resistor that plugs into the ICP sensor on the drivers side valve cover. the ICP sends a signal to the computer telling it the oil pressure being sent to the injectors, IIRC. now when you put a resistor in this plug or inline(the way i did it) you make the signal that the PCM gets lower. the lower the signal seen by the PCM, the more oil pressure that it makes the HPOP send to the injectors. Being as our injectors are run off of oil pressure, when more oil pressure is sent to the injectors, the injectors put out more fuel, therefore giving you more power.
Its not a huge power increase, but it's enough to be felt and enough to make a little puff of black smoke.
Also, if you have a programmer such as a superchip or edge evolution then doing the 10k mod is still good for some power, but if you have a DP-Tuner or Tony Wildman chip, then the 10k mod is useless.