Add "Multitasking" feature without "restoring?" 3GJB

Is it possible to add Multitasking after jailbreaking by running Redsn0w again?
I finally got my device somewhat stable. I currently use iMemory Enhancer to manage my ram and Backgrounder to manage(enable/ disable) apps running in the background. But currently none of the known app switchers(Kirikae, Proswitcher or Circuitus) work with IOS4. I removed Multitasking earlier because my phone became slower and crashed alot. This was before adding iMemory Enhancer and Backgrounder and Recent Closer. So my question is can I run the jailbreak, add Multitasking without having to do a full restore? The last time I restored(from backup) most of my app store apps weren't transferred over and had to be reinstalled, the same with my jailbreak apps. As you can imagine that's very time consuming. Anyone run a similar setup, iMemory, Backgrounder, Multitasking? Is your phone stable? Should I just forget about Multitasking on a 3G?

 

Thanks for the quick response. I'll try that! Without Multitasking or any app switcher, you have to hit the Home button then find the app icon and tap on it to switch between apps. With multiple pages/ Folders, that takes a little longer than the new Multitasking method(double tap the Home button to see/ launch backgrounded apps.)