I installed the kappas in my formula, little different set-up, but I think it's similiar. The factory amp has built in crossovers, so you should just be able to hook up the wires from the old speakers in the same config. Mark the wires before you clip them, and hook up the ones that went to the tweeter to the new tweeter and the wires from the woofer to the new woofer.
You should watch your volume levels, cause the kappas are 2 ohm, at least mine are, and I think the Factory tweets are 4 ohm. As I said I have the 2 ohm kappas in my car and have had no problems as of yet. Just be careful I have heard others on the site say you risk burning a channel on your H/U.
'01 Formula-The bolt on baby