The sides and rear where OPTIONAL for the 98-01. You can use them on a 94-97 if you buy a 98-01 rear bumper
3 holes have to be drilled for the rear valences on the bottom of the bumper no cutting. Sides go on just like the normal side skirts.
As far as buying them I have owned Real ones and fake ones i will never own the fake ones again... they worked and looked way good but only after paying a body guy to work and look good and by then it would have been the same price to buy the real ones
Only place to buy real ones... Start hunting for used ones on H-T etc... its tedious but well worth it