For the small amount of expected improvement from this groove, careful testing has to be done or the results are basically meaningless.
One of the many problems w/testing schemes like this is to do it scientifically. One concept of the scientific method is only ONE change can be made at a time. And you need a control- in this case it would be an identical unit w/o mods to test back-to-back w/no other changes.
To test on different days, possibly months apart, will not give a conclusive result unless the results are overwhelming. In other words, the changes could be so small that just different weather or ambient conditions will mask them unless the change is very large.
I would compare this to Singh grooves. There's just enough buzz to make you wonder, but when it comes right down to hard, repeatable results showing a measurable improvement, they're lacking for the most part. I believe the best thing that can be said for this is it will probably not hurt anything.