I bought a set of these and they are easy to put on.
I took them of after a short while, I did think that they were NOT strong enough in the rare case that you have to stand on the pegs.
I did replace them with a set of the more expensive Vario,s from Germany (Twisted Trottle)
They are much better but cost more .
At first I had the 30 mm extension but later I put the 23 mm on .
Yes they give a little more legroom but if you go too low you might want to adjust gear pedal (easy) and also the brake pedal (less easy
I much more preferred the Vario ones, very easy to adjust for the kind of ride you are going to have.
Twisted roads or comfort for Interstate.
Adjustable pegs that allow both a lower and more forward position are remarkably effective. Not so low as to scrape in the turns, and the forward setting provides less knee bend and more comfort.