1. Hi say it don’t need to install extension and brake line and clutch line not touching not rubbing on nothing and not like guitar string??
No, you don't need to. The lines do touch the front cover, but they are not stretched tight.
2. I’m also 5.8 and also gt bars and not fill my self comfortable full tilt to tilt on small places do turnarounds so it’s make it better??
This is subjective and I can't tell you what it will feel like to you. I'm more comfortable on the bike and I love the position and feel difference. If your bars feel a little low and far away then you'll probably like these.
See line not stretched tight: