i want to put itr cams in my car and i want to know if i woulld have to change the valvetrain

 

no, you don't have to.

 

how long to install

 

Honda upgraded the valvesprings for the more aggressive Type R cams vs. the valvesprings for GSR cams, so what do you think?
You'll only need to buy some Type R intake springs though, because GSR intake springs and Type R exhaust springs are the same. Move your GSR intake springs over to the exhaust side, install the R intake springs and your golden.