Im guessing by "front clip" you mean the whole bumper/valance assembly. It would fit if it wasnt 4" too wide. Cut it down, bend the sides in, custom mould a top peice to the bumper so it will come in to meet your grille (unless you want a 1.25" gap at the center right under the kidneys) and it should fit. Oh, yeah. You will need to fabricate a custom mount too.
If it fit an E36 then it is in no way a true E46M3 BMW front clip, unless someone did all the modifications I listed above.
If you really want the E46 M3 look get the Reiger peice, although it looks like ass because Reiger did all the mods I listed above when they made thiers.