[Samsung Galaxy Player 4.0, 5.0] hanthesolo:
NOTE: post also repurposed.

V1-

All current features of Klin's R5 rom

"universal" adrenaline shot for improved I/o Performance

Fully supercharged+Nitro lag nullifier for Optimal ram usage. (Note: if you are having bluetooth issues, unullify. I believe that worked for me.)

MANY build.prop tweaks (including smurfed out settings) for:

Improved battery life+deeper sleep

Smoother launcher

Vastly improved all-around performance

Added SQlite3, full Tune2fs, and Zipalign

Several sysctl tweaks for improved performance, and more battery life

System and Cache formatted for EXT4 by default (recommended you convert data and DBdata too!)(someone needs to verify this for me, I have already converted, so I can't tell)

Optimized Dalvik memory allocation

Beats Audio mod (amazing sound quality!)

HD youtube apk

Surface dithering (hopefully better display quality, I need feedback)

Includes Go launcher EX (someone tell me if I should not do this, but I get over 180mb free with 7 full homescreens, and 8 widgets, 2 of which are resource intensive. (fullscreen weather, and fullscreen twitter)

Increased camera and video recording quality

Disabled uneeded system apps (go into /system/app and rename them from .apk1 if you need them.)

Modded to be recognized as Galaxy S (does not work on market)

PLus several smaller tweaks I am sure I have forgotten about:p

V1.1-

did some first-day bug squashing (thanks posters!)

fixed market issue(If you have previously flashed this rom, reboot into recovery, head to mounts and storage, and format /cache)

Massive battery improvements:

Tweaked sysctl for battery (should not reduce performance)

force-disabled all swap usage (should improve performance)

Increased battery life 1.5x+

(I got over 3.5/4 hrs of constant web browsing with brightness at 30%, OC to 1.5ghz with a LOT of overvolting, and wifi on the entire time)

Gps fix for amazing lock time!

I got 3-5 seconds drom a cold boot!

V1.2-

Several small bugfixes

Ensured init.d runs on boot

Fixed some init.d scripts

Renabled logcat (for easier debugging)

Reverted busybox to a earlier version (for increased stability/ensuring tweaks stick)

small performance improvements

sysctl.conf init.d script disabled (the script is currently beta, you can enable it by uncommenting sysctl-p in the init.d script)

Updated beats audio mod (sounds a lot better)

Fixed bluetooth issues

V1.2.2-

Fixed poweramp, no more f/c

Improved audio quality

Increased max loudness of speakers (prone to distortion past 60/70%)

Hopefully squashed some bugs

Reverted possible bluetooth fix (you can still do it using my guide if your bluetooth does not work)

Possible 3d performance improvement

V1.3-

Fixed init.d scripts, they should ALWAYS run at boot now.

Fixed init.d scripts/optimized them for our device, it should speed things up a lot with my modifications (spent over 3 hours fixing them up)

removed some init.d scripts for faster boot

Fixed scrolling cache tweak (For some reason it was not working properly) for a performance increase while scrolling

General bugfixes

Added Holo launcher for total ICS feel (seemed laggy/slow when I used it though)

tweaked sysctl settings for a modest battery life increase

general performance fixes/increases.

V1.4-

Advanced sysctl tweaks (super fast responses)

Improved battery life a bit

Gave Ram priority to system (should not affect you unless you are a HUGE gamer, as in running games that should not be able to run on the Gplayer)

Small performance tweaks

Improved boot time ~5-10 seconds

Cleaned up init.d scripts some more

Tweaked Beats audio for better poweramp compatibility (hopefully)

Small tweaks to supercharger

Possibly fixed potential bootloops

V1.5-

Tweaked sysctl for added performance

Drastically improved battery life

Removed Holo launcher (unecessary and drained a LOT of battery when in use)

Added launcherpro (recommended for use to save battery life)

Tweaked build.prop for improved performance

Fixed nitro lag nullifier (bluetooth fix works 100% now)

Added CM9 wallpapers

Changed EXT4 journalling method (Big I/O boost)

Tweaked init.d scripts a bit

Updated/bugfixed busybox

Added voodoo sound control as a system app

Improved UI smoothness/performance

Disabled more uneeded system apps

Fixed home button issue (check my howto section)

various bugfixes/performance improvements