What if your Improvised Weapon is Exotic?

[Meirril]

So I've been playing around with the idea of abusing Shikigami Style plus its 2 other style feats, Catch Off Guard, Suprise Weapon for a free +2 to hit.

Then I started looking through different items that qualify as Improvised Weapons and I found Sledge. This counts as an Earth Breaker. The d20PFSRD counts that as exotic, but Nethys says it is Martial and Nethys is official so...anyways I still want to think about this.

If the class you have doesn't give you proficiency with the weapon equivalent to the improvised weapon you are using, do you take a penalty for non-proficiency on top of the improvised weapon penalty? Even odder, can you treat actual weapons as improvised because you'd have a bunch of benefits from just getting something that performs close to that weapon rather than the actual weapon?

Do you allow improvised weapons to be enchanted? If someone has an improvised weapon crafted out of a special material...does it stop being improvised?

Also, is there a 3rd feat that has Shikigami Style as a prerequisite? I could only find 2.

[avr]

There's only 2 feats with that style as a prereq. Including the style itself that takes you up to the maximum 3 step size increase.

You can apparently buy mithral waffle irons. I would still count these as improvised weapons. Enchanting them as weapons is out I think, but gloves of improvised might are the official workaround.

No idea about the proficiencies.

[Jared Walter 356]

from CR pg 144 Improvised weapons:
"because such objects are not designed for this use, any creature using that uses an improvised weapon is considered nonproficient and takes a -4 penalty on attack rules with that object..."

The way I read this is that the -4 attack penalty is because you are not proficient. In other words, is the same as not-proficient and doesn't stack.

In theory, any weapon not being used as intended is improvised, which changes its critical to 20 (x2), and incurs the -4 to hit. I suppose you could hit someone with the handle end of a shortsword for example.

I would not allow improvised weapons to be enchanted. Enchanting requires starting object to be masterwork. In other words, exceptionally well built for its intended purpose which seems mutually exclusive to improvised (not used for its intended purpose).

Materials seems quite reasonable to me. For example, it would be conceivable that someone would build a adamant shovel for digging. When used as a weapon it is improvised (not used for intended purpose), but would still be adamant.