In my opinion it would be easier to buy a new car :-). But seriously, you would need to change not only the mechanicals, but also the electronics. Let me go over a rudimentary list of both:

mechanical:
1) install the pump (the big "thing" next to the coil).
2) change the master cylinder (or at least the reservoir, because you need that level sensor in place of the octopus's pressure comparator that you no longer have because you no longer have two independent triangular braking circuits -- now it's front and rear, btw.
3) change all the metal brake lines (and also get rid of the pair of rear proportioning valves), because they have to be rerouted into and out of the aforementioned pump.
4) change the front calipers, which are now single circuit (one line) instead of the old two line types.
5) change the front hubs and spindles to accomodate the tone rings (and the electronic pickups) to measure the speed of each front wheel.
7) change your rear axle to one that has the inside parts that can serve for both the electronic speedometer sensor and also the ABS sensor (the ABS system is three channel, two for each front wheel and a third for the common speed of both rear wheels). Axles with just the speedo capability have a smaller number of teeth in the tone ring than one with both capabilities, I suppose to make the ABS more sensitive.

Electronic:
Where to begin?!!!
You need to install virtually an additional computer (microprocessor) system complete with its power and sensor cables, warning lights, etc. Too numerous to count. And integrate it into the car's existing electronics controls.

Whew.

Still interested?