According to the Magic Item Creation Rules, one can add the benefits of a spell to an item continuously for a price of Spell Level x Caster Level x 2,000 gp. There are modifiers for the spell duration, but the spell I am interested in, Owl's Insight, has a duration of 1h which is the basis.
Now, Owl's Insight is perhaps one of a kind in that it grants an Ability bonus directly tied to the Caster Level: +1/2 CL Insight bonus to Wisdom.
This is pretty unusual, as it means that its pricing is very different from other bonuses to Abilities:
- Enhancement bonus: +N -> N x N x 1,000 gp
- Other bonus: +N -> N x N x 2,000 gp
- Owl's Insight bonus: +N -> N x 20,000 gp
The initial price is steep, as it is only more advantageous than using the "Other bonus" formula once past level 10, however it grows linearly instead of quadratically, and since there is little limit to Caster Level, one could potentially obtain a ridiculously huge bonus (after Epic).
There is also no limit given to this bonus since it based off the Caster Level which is virtually unlimited.
Now, if one uses the -30% from being restricted to a class or alignment, one could in theory get more than a +10 bonus pre-Epic (<= 200,000 gp ?):
- Max Enhancement bonus: +16, for 179,200 gp
- Max Other bonus: +11, for 169,400 gp
- Max Owl's Insight bonus: +14, for 196,000 gp
So, I would have two questions:
- Are the limits on the magnitude of bonuses (I often heard that Enh. bonus to Ability cannot exceed +6 pre-Epic) solely designed by comparison with published items or are there rule(s) pointing at absolute limits to distinguish pre/post-Epic gear?
- Will a magic item that costs around 200,000 gp that grants my character a constant +14 Insight bonus to Wisdom unbalance a level 20 campaign knowing that it governs its spell-casting ability?