iPod touch 2G Downgrading Questions

[Turismo]

I updated to 4.0, and it works great. Not much different but it works still. But every since i updated to 4.0, my iPod would randomly reboot into Recovery Mode. If you try and restore with iTunes you would get a Error 1611. After about 2/3 hours, if i boot the iPod up it would boot up normally and would work normally again until the next time it randomly reboots into Recovery mode. Sometimes it does this when i go on AppStore, or Facebook, Safari. Other times the iPod would randomly reboot, this happened when i turn off airplane mode, and when i installed BBC News. It reboots randomly, sometimes it reboots okay, other times it reboots into Recovery mode, and i have to wait for 2/3 hours to boot it normally. And it is really ANNOYING! I have restored 3 times, and have restored once on a different computer. Since none of these worked, and my problem still persisted, i am thinking about downgrading to 3.1.3. I have seen the Tutorial on this website.
But i have some questions.

1. Which iTunes version do i need to be able to downgrade?

2. Does the tutorial also work for iOS 4.0 Final?

3. Will RecBoot work to boot the device out of Recovery mode instead of using iRecovery after the restore has finished?

Thanks for you help

And is anyone else experiancing problems like this on their iDevice? I seem to be the only one.

iPod touch 2G MB Model 16GB

Another question off topic:

If I jailbreak but my device is stuck in Recovery mode will Apple know whether the device is jailbroken? Will they find out once they run the Diagnostic Scan they use on their Macs?

Thanks!