  In this paper, we address the possibility of upgrading the ILC250 luminosity
to $8.1 \times 10^{34}$, so that with the polarization feature, the effective
luminosity will be $2.0 \times 10^{35}$ to compete with the FCC-ee luminosity
and two detectors. The additional cost of the higher luminosity option will be
about 2.2 B ILCU. The total cost for the ILC high luminosity machine will
therefore be about 7.7 B versus FCC-ee 10.5 B. The AC power (267 MW) to operate
the ILC luminosity upgrade will also be less than the AC power for FCC-ee (300
MW). Even with a modest quality factor Q of $1 \times 10^{10}$ for SRF
cavities, the total cost of the upgrade will be 2.5 B ILCU additional over
ILC250 baseline. We expect that, if approved, ILC250 will first be built at the
baseline luminosity, operated for many years at this luminosity, and later
upgraded to the high luminosity option. A significant part (RF power and
cryo-power) of the additional cost for the luminosity upgrade overlaps with the
expected additional costs for anticipated energy upgrade paths. A second ILC
upgrade discussed in this paper will be to the higher energy Top Factory at 380
GeV. We also estimate the additional cost of this upgrade (1.5 B ILCU).
