I would like to gently customize a ROM for myself. I unzipped the latest one from XDA, and found subfolders much like those seen with ADB on a live phone. I want to do such thing as remove specific bloat apps, put in a Phone.apk with my own default caller pic, and a custom boot. It LOOKS like all I have to do is remove or replace the files, just as I would do in ADB, rezip the rom, and install. I assume I would zip with no compression. Is it really that simple?