[G3 General] :
It's placebo. Most of lines won't even work on g3, half of others are already present in G3's default build.prop... Pls do some research before posting.

Line-by-line:

persist.sys.composition.type=c2d // Already in default buid.prop

persist.sys.scrollingcache=4 // Disabling scrolling cache on 2/3 gb RAM phone? Lolwut?..

persist.sys.purgeable_assets=1 // Purge unused assets. May free more memory. And give some lag due to these assets being loaded from sd, instead of ram.

dalvik.vm.heaptargetutilizag.composition.type=c2d // Used by default in g3

debug.performance.tuning=1 // LOL? You know, this variable doesn't even exist in ICS and latter codebases... It's 2.3 and earlier only...

debug.enabletr=true // Permanently disables hardware overlays. That's what gave you speed boost in exchange for BUGS in youtube and other apps...

debug.qctwa.preservebuf=1 // Something QUALCOMM related. No info on that one.

dev.pm.dyn_samplingrate=1 // Enables dynamic sampling. Something from 2.3 era.

video.accelerate.hw=1 // G3 uses hw acceleration to render videos by default, no need for that line...

ro.vold.umsdirtyratio=20 //Well, you know, G3 doesn't use UMS. So that tweak is useless.

debug.overlayui.enable=1 // should be disabled for performance gains.

debug.egl.hw=1 // Enabling hw debug won't increase performance.

ro.fb.mode=1 // disabling cpu rendering isn't the smartest idea. "How to drain your battery dry fast due to hardcore usage of gpu, volume 1"

hw3d.force=1 // useless on g3.

persist.android.strictmode=0 // may help those who run badly written apps with pieces of debug code in them.

persist.sys.ui.hw=true // LOL RLY? G3 already renders ui by hw+cpu combo.

ro.config.nocheckin=1 // Should disable sending some debug data to google. Harmful to everyone using droid.

ro.vold.umsdirtyratio=20 // Ummm... Did you repeat yourself?..

dalvik.vm.checkjni=false // will crash badly written apps, unnoticable speedup for other apps. And only if these apps use JNI, which is not many...

dalvik.vm.execution-mode=int:jit //Lol wut? jit is used from 2.3 onwards. No need to use that.

profiler.force_disable_err_rpt=1 // How NOT to help developers debug their apps.

profiler.force_disable_ulog=1 // Same thing.

ro.media.enc.jpeg.quality=100 // G3 doesn't care about this property. Edit media_profiles.xml instead

ro.telephony.call_ring.delay=0 // G3 doesn't care.

windowsmgr.max_events_per_sec=1200 // Read this..

ro.max.fling_velocity=20500 // Same as above

ro.min.fling_velocity=18500 // Same as above

ro.min_pointer_dur=8 // Eh. Pretty useless on G3, it's screen in already very responsive.

pm.sleep_mode=1 //Read this

ro.ril.disable.power.collapse=1 // Does nothing.

debug.performance.tuning=1 // Something from 2.3 era. Shouldn't work now.

video.accelerate.hw=1 // Hmm, i believe i saw this one already..

ro.media.dec.jpeg.memcap=12000000 // G3 doesn't care about this property. Edit media_profiles.xml instead

ro.media.enc.hprof.vid.bps=12000000 // G3 doesn't care about this property. Edit media_profiles.xml instead

media.stagefright.enable-player=true // Already used in default build.prop

media.stagefright.enable-meta=true // Already used in default build.prop

media.stagefright.enable-scan=true // Already used in default build.prop

media.stagefright.enable-http=true // Already used in default build.prop

media.stagefright.enable-record=false // Already used in default build.prop

ro.config.hw_menu_unlockscreen=false // Allows menu button to unlock the phone. Thing is,

G3 DOESN'T EVEN HAVE HARDWARE MENU BUTTON LOLOLOL

persist.sys.purgeable_assets=1 // Hmm, i saw that one.

ro.mot.eri.losalert.delay=1000 // Delay between "service dropped!" alert happening and android reacting to it. Do not touch.

ro.config.hw_fast_dormancy=1 // Again, G3 doesn't care. It has it's own list of service providers with needed setting, it knows when to turn it off and on.

ro.ril.enable.amr.wideband=1 // Already enabled.

ro.lge.proximity.delay=25 // G3 doesn't have "black screen after call" problems. Do not touch.

mot.proximity.delay=25 // G3 doesn't have "black screen after call" problems. Do not touch.

persist.sys.use_dithering=0 // Disabling dithering isn't smart.

persist.sys.use_16bpp_alpha=1 // Improves performance, drops visual quality.

force_hw_ui=true // I remember seeing this line TWICE ALREADY.

hw2d.force=1 // Eh. G3 knows what to render with what. Do not touch.

hw3d.force=1 // Eh. G3 knows what to render with what. Do not touch.

ro.opt.zerowakelag=true // Eh. Even sounds stupid. Zero wake lag means no deepsleep, so if this tweak works - it drains battery like crazy.

opt.zerowakelag=true // see above.

ro.HOME_APP_ADJ=1 // Not like G3 cares about it. He'll still unload the launcher. It's better to give it -10000 priority via different tools.

ro.HOME_APP_MEM=1024 // You know, that setting need to be heightened in order to gain performance improvements, not dropped to 1024...

dalvik.vm.dexopt-flags=m=y,o=v // Oh, finally. This one actually works, gives minor improvements to performance.