Here's a modified build.prop Ive tested on my Thrill. It includes a lot of the tweaks posted in various links but already packed into a build.prop.
I have tested to make sure that this build.prop will NOT break your phone. Im running this build.prop on my Thrill with no issues what so ever. Actual improvements from these tweaks are up to you to test. I make no claims to their actual effectiveness.
To use this just put it on your sdcard and rename it to build.prop (its currently just a .txt file for upload purposes). Then paste it into your /system partition using a root file explorer such as root explorer or estrongs.
Here's a list of the actual changes and what they are supposed
ro.HOME_APP_ADJ=1 Keep home launcher (any) persistant in memory
ro.telephony.call_ring.delay=0 make phone ring faster when dialing out
ro.lge.proximity.delay=25 disable blackscreen issue after call
mot.proximity.delay=25 same as above
windowsmgr.max_events_per_sec=150 Better scrolling speed
wifi.supplicant_scan_interval=250 increase time between wifi scanning to save battery
pm.sleep_mode=1 save battery?
ro.ril.disable.power.collapse=0 save battery?
debug.performance.tuning=1 increase touch responsiveness
video.accelerate.hw=1 goes with above mod
debug.sf.hw=1 render ui with gpu
(potentially taking some load off cpu?
ro.media.enc.jpeg.quality=100 increase jpeg quality to max
persist.adb.notify=0 removes the debugging mode notification from status bar
The following are all meant to improve 3G speeds
Net speed tweaks
Those are just the ones I know will NOT brick/bootloop your phone. Feel free to remove whatever you dont want to use. All additions are at the end of the file. So all you rom devs feel free to include them in your roms. If anybody has any more they've tested let me know so I can add them. And ill update the build.prop as I test more tweaks.
EDIT: Included the original build.prop file (original_build.txt). Just rename it to build.prop and stick it on the /system parition.