If I want a specific look and I find a piece of moddable armor or item that is prototype level, can I take that piece and slot 80 mods into it to make it an IR 306 piece. Or would the same item as an artifact be better?

The gear that gives you stats and the outfit that determines how your character looks can be different. You can look at SWTOR Gear vs Outfits Guide: what is the difference for details.

If I want a specific look and I find a piece of moddable armor or item that is prototype level, can I take that piece and slot 80 mods into it to make it an IR 306 piece. Or would the same item as an artifact be better?

As mike said, if you use Outfit Designer slots for your *look*, the question becomes irrelevant. Put the thing you like the look of in an OD slot and never worry about what your stat gear looks like, nor whether it's Premium (green), Prototype (blue), Artifact (purple) or Legendary (yellow), not whether it is fixed-stats or moddable. Only the gear in the un-numbered slot (with a small human figure instead of a number) matters.

 

As for the details of the question:

* When you put mod-objects in a piece of gear, its inventory colour will change depending on the inventory colour of the armoring/barrel/hilt (I believe).

* At level 75, you should prefer to use "set bonus" gear, but of course the set bonus is on the moddable shell, not the armoring, so if you don't want to look like the set bonus shell looks like, you *have* to use Outfit Designer.

 

But in the end, the "base" (not-modded) colour of a moddable piece of gear is of no importance.

If I want a specific look and I find a piece of moddable armor or item that is prototype level, can I take that piece and slot 80 mods into it to make it an IR 306 piece. Or would the same item as an artifact be better?

Yes you can. The stats would depend upon the mods only - not the "colour" of the shells.

But as pointed out, using an "outfit" would be better.

The usual thing, once you get to level 75, is to have a base set of "bonus" armor and your 'look' in an outfit. (Partly because most of the bonus gear is butt ugly.) 🙂

 

Notes about outfits:

You can have a piece as your main base armor and in an outfit(s) at the same time.

After 'stamping' a piece in an outfit slot, you can wear it as base armor, or keep it in storage, or put it on a companion, or whatever.

Pieces stamped in an outfit don't need mods or stats. They can be any 'colour'.

Edited January 15, 2021 by JediQuaker