http://www.chi-tai.info/cs_BatterySt...s.htm#Download
I use that to keep track of the memory left in the device as well as tracking how much space is left for programs on the device as well as the SD card. Also do u delete ur internet explorer history? Cause that can also take up memory on ur device and slow it down. I also use stock rom the only diff. is that i'm verizon, but that doesn't really matter much in this case.
BTW, i don't remember which version of the Battery Status i'm using, i've had it since jan i guess u can say (or somewhere around there).