1.) once 2.2 is rooted will there be any differecnes from a rooted 2.2 phone running a 2.2 rom and a rooted 2.1 phone running a 2.2 rom...basically should i get the new phone (2.1) and root it to a 2.2 rom or wait for 2.2 to get root and then upgrade it to 2.2 and then root.
2.) what rom should i run if i want 4g, wifi tethering, and 30fps fix.
3.) How hard is it to go back to stock once its been rooted
Good questions, especially the first one. Here are the correct answers with plenty of hopefully non-confusing answers.
1) There is no difference between flashing a rooted 2.2 stock rom from an existing 2.1 rooted build and a future 2.2 root exploit that roots your existing 2.2 stock build. The end result is the same. There was ABSOLUTELY NO advantage for people to give up their root powers to receive the stock 2.2 OTA update. A rooted version of the STOCK rom was created between the time the leaked 2.2 and official OTA 2.2 were available. If people had the patience to wait 1 or 2 days, they would have been able to enjoy the stock 2.2 features and kept their root.
Repackaging a ROM so that it is rooted is a very quick process. As soon as the stock ROM is released, the devs repackage it with root so that EXISTING rooted users can flash this repackaged ROM to upgrade their phones and preserve root access. People with non-rooted phones don't have the ability to flash custom ROMs, so they cannot use this repackaged ROM. So step 1 is to jailbreak your phone (root it, unlock Nand). Step 2 is to flash a ROM of your choice. Step 3 is to maintain your root by never flashing a non-rooted stock ROM or accepting an OTA update.
2) You can have 4G, wifi tether, and 50+FPS with the stock ROM but replaced with a custom kernel. A ROM can contain multiple components, and the kernel is almost always bundled. When you download a reputable ROM, you are getting a custom kernel and a custom operating system, and most reputable ROMs' kernels have already been modified to give you the wifi tether, the 4G, FPS uncap, and CPU throttling. The operating system part of the ROM has nothing to do with any of these features; that's why you can get away with a stock rom with a custom kernel. See my sig if you prefer to stay as stock as possible.
3) Unrooting is as simple as flashing an unrooted ROM. However, there are different degrees of unrooting, just like there are different degrees of rooting (the proper term should be jailbreaking). You can unroot from an application-side standpoint, meaning applications won't be able to request superuser permissions. But you can still keep a custom recovery image and the engineering bootloader. These components, strictly speaking, have nothing to do with "root," but they allow you to obtain root again by providing a pathway to flash custom ROMs. Having an engineering bootloader with a custom recovery means your phone is fully jailbroken (not necessarily rooted, because you could flash a non-rooted ROM that doesn't overwrite your recovery image or bootloader image). If you want to truly return to stock, you need to run a ROM Upgrade Utility (RUU) that will replace your bootloader and recovery with the stock versions, and return your OS to stock without root. You can find stock RUUs floating around the web.
There are two reasons why you would ever get rid of root:
a) you need to take advantage of your warranty for whatever reason. make sure you fully unroot (put your phone back in jail)
2) you decide maintaining a rooted phone is too much hassle. Here, I'd recommend flashing a non-rooted ROM that preserves your engineering bootloader, so you have the option to get root back at any time without needing an exploit to break in to your phone.
The engineering bootloader is obtained when you follow a root exploit that fully jailbreaks your phone (Simpleroot, Toast's method, currently only functional on 2.1). Unrevoked3 will root your phone but won't fully jailbreak it. It's commonly referred to as a half-root.
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