Can you change jailbreaks on your jailbroken ipod?

Like, idk how to really explain this, so try your best to understand what im asking if it makes no sense. Kso, i have a ipod touch 3G and i have it jailbroken with blackra1n. Now, there are no untethered blackra1n jailbreaks for 3G, and its really annoying because everytime my battery dies or something, or if it randomly turns off, i have to plug it into the computer and run the jailbreak again. Well my question is, if i were to change my jailbreak to spirit, which is untethered for all devices, would i lose everything i got from my blackra1n jailbreak? like all my themes and third party apps?