The Dynacord DSA8212 amp would work fine bridged mono into a single 4 ohm TH-118.
You would need three more if you want to use the dynamic range the TH-118 can handle.
Their peak power of 3400 watts is good, but as Paul (and Ivan) have suggested the long term limiting should be set to about 1/4 that.
That was my take as well based on the specs but others suggested it might be OK to run one sub per channel? I guess I just try it out and listen?