"These springs can handle 12k+ RPM with any camshaft ...." OK, but let's have some actual specifications, please.
What is the spring pressure at what open valve heigth? How much do they weigh? What are stock Honda spring specs?
Stronger springs use horsepower, wear the valve train faster. 12k+ RPM engines don't last long. These sound like full race springs.
Another option between this and stock would be nice for big cam, big valve, 10k redlines, which would really extend reliability.
After years of not locating the ultimate valve spring, we decided to have our own made. These springs can handle 12k+ RPM with any camshaft available and have been designed to not need an inner spring in order to keep valvetrain weight low. Compatible with stock or our titanium spring retainers for the ultimate float-proof valvetrain setup.
Fits: 2014-2020 Honda Grom/Monkey