Sounds interesting - but actually, what is the necessity behind such an addition? The engine should be designed to withstand those vibrations also without those additional struts and braces; tying parts together that are not meant to would change the vibration patterns and possibly induce loads on parts that were not meant to bear them. Compare an unbraced cylinder moving like a reed (hinged on one side) vs. a braced one vibrating like a string (hinged on both sides) - the bending moments seem rather different.
Thast's what I was thinking. Additionally, if you have two adjacent cylinders vibrating up and down, 180 degrees out of phase with each other, he you tie the heads together that would introduce a moment around each cylinder's axis which didn't exist before.
It's worth noting that nowhere on that site could I find any reference to an STC for the modification. That would lead me to believe that there isn't one, which means it's for experimental aircraft only.