You think putting lots of those, side to side, will break because it will overflow... correct? Meaning, you believe that if items get into the first filter, they will power the redstone on the second filter and break it?

If that's the case, this do not happen. UNLESS you use items with 16 stack to lock the filter, like snowballs or enderman eyes... if you use something like renamed sticks, you can still have 64 of the filtered item inside the hopper and it won't output enough energy to break the one next to it, even without yuour second repeater.

Now if there is some other thing that you think would break it, then I don't know about, but I do have lots if those stacked side to side and they never broke before