Pellet stove outside air intake install

[Mholliday26]

Let's first say there is a million opions on installing outside air intakes and if it's worth it, for my house I need it. I own a Harman accentra insert that's in a river rock fireplace with no clean out. My two opions were drill a hole through the nice looking fireplace and install a intake which would be right next to the front door or go up the chimmney with a 3" pipe and out the top plate with a 90 deg. My exhaust is a 4" that goes to the 6" liner that was there from a old woodstove insert. The right way would be to rove the 6" and insert the right liner which I was quoted to be $1000. The top of my chimney is a 13x13 plate with a 6" hole for liner with a storm coller on it making 1" on each side. So I am looking to see if anyone has any ideas on what i should do I thinking of removing the storm coller and caulking the liner in which would leave me witj 2" in each side