I've never gone more than +1, but in my experience, no. Why do you ask?
It is rare (or perhaps non-existent) that an
e-liquid will "ruin" a vaporizer (and by vaporizer, I think you're talking about heads ). The exception is
tank-cracker juices (which will destroy many types of plastic heads) but these are a problem no matter what the flavor concentration is, just might take a minute or two longer to realize you have a problem.
Flavor shots can cause a coil to gunk up sooner than it would have, since it's the flavors that do most of the "gunking". Even so, a dry burn, or soak in vodka will remedy the situation most of the time.