[HTC Wildfire S] bobdamnit:
This is basically true, unless you have advanced Android modification knowldege. I can get a few Virgin Mobile ROMS working, as well as just about any MarvelC stock ROM.

Before you go custom ROM, I would recommend (if you haven't) unlocking your bootloader through HTCDev.com. (You kind of have to do this, unless you opt to unlock a different way.) Download HTCSync and install it, then download the RUU through the "unlock bootloader" option. (You'll have to create an account.) The RUU option has to be performed in Windows.

Once you unlock your bootloader, go here:

http://xdaforums.com/showthread.php?t=1074445

and download the new MetroPCS RUU to update your bootloader to 1.10.0000. This will ensure that the MetroPCS ROM you are running is built from the Marvelc hboot instead of the Marvelct hboot that originally came with your phone. This is an excellent update, and should be performed by all MetroPCS users. It really does help out a LOT of anomolies on our phones ;)

After that, go here:

http://xdaforums.com/showthread.php?t=1213229

And follow the instructions to install ClockWork Mod recovery. You'll need it for installing custom ROM's, as well as setup custom partitions on your SD card. You MUST remove this file from your SD card after it has been installed. Otherwise you will always attempt to install CWM recovery. Once you get this installed, reboot to the RUU by rebooting the phone. Shut down normally, then pull the battery and replace it. Hold Volume Down+Power until you boot into hboot. After it does the update checks, select "recovery" and boot to CWM. Go through the menu and find "Wipe user data/factory reset" and use that. Then go to "Advanced" and format "Dalvik-cache". Then, in the "Advanced" menu, select "Partition SD Card" and use this as the following values:

EXT Partition: 1024MB/1Gb

SWAP: 256 (This is not necessary, but CWM insists you use it...)

Let it do its thing. Once its done, back out until you get to the main menu in CWM. Go to "Mounts and Storage" and connect your phone to your computer with HTCSync installed. On the phone, select "Mount USB Storage" so that the phone picks up as external storage.

insink71 came up with a stock MetroPCS ROM that works pretty good. Its stock with root and a2sd capabilities. This ROM is here:

http://www.mediafire.com/download.php?832o9otiu6713m8

Download this to your SD card on your phone. After you get this downloaded, unmount the phone from the computer through CWM. Back in the main menu of CWM, find "Install zip from SD card" and select that. Find "Choose zip from SD card" after this, and then find the MPCS ROM and flash this.

After you get this up and booted once, log into Google and access the Market to download "Terminal Emulator". Fire this up and accept Superuser rights. Once Terminal Emulator starts, type the following (Without quotes!!):

"su"

"a2sd zipalign"

"a2sd cachepartreset"

"su" grants Terminal Emulator Android super user permissions. "a2sd zipalign" will zipalign your apps to the EXT partition, and take MUCH longer to boot the next time you reboot. "a2sd cachepartreset" will flush Dalvik-Cache and move it to the SD-EXT partition, removing a bunch of extra space that could be on the SD card.

This basically allows you to install a LOT of apps without having to worry about running out of app space. ;)

There are overclock kernels, but I don't recommend any currently. I can get one to work for me, but others dont. Currently, I don't overclock my phone.