2001 with four lugs would require a five lug hub, calipers, rotors, brake lines, possibly the master cylender, brake pads of course, and five lug wheels, and you'd need to do it for front and back to have proper perportioning, plus wheels to match the five lug pattern.
Only 2001+ ES are equipped with rear discs and were also equipped with 5 lug wheels. The equipment listed above is a pretty good detailed description. There were some 1st gen pros with rear discs, but the 98-2000 ES had drums on the US models.
could you explain that a bit more.....does that just mean the brakes would squeeze at different forces (unless both front and rear are replaced with same equipment) causing the car to possibly brake unevenly and lost control?
Yeah, there may be a difference in force between the two different models of car, if there's any difference in the lines/brake booster/master cylender. But since they're so similar, I doubt it, to be honest.