Sounds like what is being asked is 'should I add another radiator to my loop' and 'will this make a difference'.
This depends.
6700k chips always reported higher temps due to Intel using junk thermal compound between the CPU cores and the IHS, which is why a lot of people have delidded them to reapply better compound like Thermal Grizzly and others. I even considered it because I did see temps about where you are seeing them and I had minimal space in an mITX case at the time.
The reason 'it depends' is because there are often exceptions in how well these chips perform, but I don't think that adding another radiator is going to significantly drop your temps. One thing that wasn't mentioned is whether your CPU is overclocked or running at factory speeds/clocks? Mine was stock speeds and depending on ambient room temperature, this could be as wide a swing as 5-7C at load with Prime95. This could be in the low 50's C and up to 60C, depending on how warm my office was at the time (summer/winter).
Long story short - you don't need an entire additional kit, at most you would need a radiator, fittings and tubing to add it, if you do anything. Again, I don't know that going bigger than a 360 rad is going to make that much of an impact unless you have a significant CPU overclock going.