[Scotsgit]

Have used Stop&Go tyre plug system for years.
Mainly for motorcycle use but equally at home on a car tyre.
It uses a compression tool to push a mushroom shaped plug down a guide tube into the tyre.
No glue required.

 

[Scotsgit]

Have you used these as a permanent fix?

Personally, yes.
I have used them in motorcycle tyres for thousands of miles until the tyre due for replacement.
I have also used them on car tyres for many thousands of miles.
I would only recommend where it is a simple nail or screw hole though.
The website does not commit itself, says as they are mushrooms they will be fine, then they also say that tyre manufacturers recommend a "professional " repair or replacement.
I have no concerns about using them as a permanent fix on my cars or motorcycles.