Can i do the same to GTR2 plr file?
Pretty much, but you won't see quite the same performance boost. There was something very wrong with GTL's implementation of the trackside characters which results in massive slowdown for that particular settings. Here are the GTR 2 equivalent settings in the .plr file:
(Ones marked in bold have most effect in GTR2)
Data Acquisition In Race="1" ---->change value to "0"Driver Animations="1" ---->change value to "0"
Track Animations="1" ---->change value to "0"
Disable All Character Anims="0" ---->change value to "1"
Windscreen dirt buildup="1" ---->change value to "0"
Swaying Trees="1" ---->change value to "0"
Arms Visible In Cockpit="1" ---->change value to "0"
All these settings are things you will barely notice at all, so are definately worth turning off for the performance gain you get.