Hey friends been a while!

I picked up my Iphone 4 last evening and want to move everything from my JB 3g to the 4.
Am I on the right track:

1. Remove all apps from Cydia categories app.
2. complete back up with Itunes
3. plug in the 4 and and synch.

Questions:
If I do a complete wipe using the 3g's program in settings does this remove the JB?

I want to JB up to 3.1.3 as I'm awaiting the the speed fix issue for OS4. If I use Pwnage tool can I do this just the same as before, even though Itunes will recognize the Iphone 4 as the last device synched? (i hope thats understandable! )

Thanks!!