If I am reading the description correctly, it looks like one of these is statted as follows:
Heat: -4
Weight: 1.5 tons
Crits: 3
Compared to existing ISDHS:
Heat: -2
Weight: 1 tons
Crits: 3
And vs two Clan DHS:
Heat: -4
Weight: 2 tons
Crits: 4
This is a major boost in capability and except for the fact that it can't fit in a Mech's legs, is better than Clan DHS.
For Periphery heat management tech, I'd suggest just loading the Mech with a giant tank of water and treating that as a Heat Sump. All heat goes into the Sump first, then into the Heat Scale. Heat Sinks take heat from the Heat Scale first, then from the Sump. Gives a reason for Mechs to have an Alpha Strike capability, is relatively low-tech, is less effective than extra Heat Sinks, and can boil water for a pot of coffee.