When I turn a nice weapon with auras on it into the golem itself, does the level matter on the aura or no?

is lvl 17 insight better than 14 insight for iron golem for my overall mana regen on my necro himself?

yes. the golem takes the stats of the item, so the aura level on golem is equivalet to the aura level of the item

Thanks, confirmed by everyone?

Yes