Over the phone estimates are $250 to $300, assuming that there are no other problems.
The uniqueness of the head was just the depth to the top of the plug hole, not the thickness of the head, anything like that.
https://www.denlorstools.com/page_41041 ... nsert.html is confirmed by the DenLors to be correct for a '00 i30..
The cost, now we are around $230: kit, insert, Loctite, small (less than 14mm, needs to fit through the spark plug hole, into the cylinder) hose to attach to a shop vac.
So, we have
should work for $120 or so (kit + shop vac hose) + 2 to 4 hours personal time doing the work,
is expected to work for $230 + 2 to 4 hours personal time doing the work, or
at a shop for $250 to $300, plus 2 to 4 hours personal time, tow there, wait, drive back.
I have successfully done a Heli-Coil insert before. Patience and paying careful attention to details are important, as they are with most shade-tree mechanic fixes.