Ben, you should keep to just reading the posts because you obviously don't no what your talking about little boy !!!!!!!!!!!!!
The inserts will NOT fit any of the standard cylinder heads, ONLY the "Stars" one....
They do make quite a big difference though once fitted, the High compression is the best option for the 125 as the very high is kept for when riding in places like Andora to get more power out of the bike, if you use the v.high straight away there's no way to get more power out of the bike.....