You will not be able to use much of the comp's power in 2wd on snow or ice. As a matter of fact you will not be able to use much of your trucks stock power in 2wd on snow/ice. I drive more than half the year on snow and ice and I have to leave it in 4x4 ALL the time. Last wintert I had an EZ, 275 injectors, and a PE installed. I set the ez to the weakest seting (extra fuel starts above 20 psi) and left the PE off and still had several 2wd burnouts at 60 mph on the ice.
Another word of advice, don't use your curise control in 2wd on snow and ice. If you drive up an icy hill with the cruise on the computer sensese the slow down and pours the power to it and your rear wheels will start spinning and you will be out of control in a hurry.
My advice to you, install the comp and set it to a real low setting. Then put it in 4x4 and take it easy. Nothing is worse that going on a trip to have fun and then not having it.
Check out the winter fun link in my sig... .