Staff Magus w / o Spell Strike and Tripping Staff

[Alexander Augunas]

Staff Magus is a magus archetype from Ultimate Combat that has tons of cool staff-based options. Buried in another feat, Tripping Staff, is a line that notes that you can use spellstrike on any trip combat maneuver that you make with the staff. [url="http://www.d20pfsrd.com/feats/combat-feats/tripping-staff-combat"]Here's a quote for reference.

PRD wrote:

Tripping Staff (Combat)

You can make a trip attack with your quarterstaff.

Prerequisites: Int 13, Combat Expertise, Improved Trip, Weapon Focus (quarterstaff), base attack bonus +6.

Benefit: You treat quarterstaves as if they had the trip special feature.

Special: If you are a magus with the staff magus archetype, you can use spellstrike on any trip combat maneuver you make with the staff.

Obviously, this feat is assuming that if you are a staff magus, you still have spellstrike (staff magus does not trade this ability away), so it makes this clause.

However, there are archetypes that replaces and/or modifies spellstrike that stack with staff magus. A prime example is the new Card Caster archetype from the Harrow Handbook.

Card Caster has an ability called Harrowed Spellstrike that replaces and modifies spellstrike, allowing you to spellstrike only with ranged weapons.

Simply put, my question is "How do abilities that replace or modify other abilities interact with one another?" I'm assuming that this is going to have to be a case-by-case basis. My gut tells me in this case that Tripping Staff would not allow you to use Harrowed Spellstrike with your quarterstaff because it replaces Spellstrike with a new ability.

That said, an FAQ on the subject of how replaced and/or modified abilities interact with options that assume the base, unmodified version of that same ability would be helpful.

Any thoughts?

[Kazaan]

You shouldn't be relying on your gut for these kinds of deductions; a brain does a much better job. However, in this particular case, the brain must agree with the gut; the feat allows you to spellstrike with a trip maneuver executed with a staff while Harrowed Spellstrike allows you to spellstrike only with ranged weapons. Since you have no way to execute a trip with a staff at range, the technical combination of the two is fundamentally impossible to pull off.