Credit for all of this goes to @autoprime and @nicotheandroidguy
A few notes: I used Windows 7 for the odin flashes , my phone is a SPH-L720 and it is not active on the Sprint network, also the sim card from t-mobile was inactive (brand new from t-mobile store.) and it has a bad esn. I am located in the Phoenix az market so I'm able to take advantage of the 1900mhz band that tmobile has here.
I'm unsure of how this will work with mnvos or other primary carriers and frankly I don't care at the moment, this is my primary phone. Update: confirmed hspa+ for tmobile, metroPCS, straight talk and AT&T.
I HAD MY NEW UNACTIVATED TMOBILE SIM CARD IN THIS ENTIRE TIME
1) First I reverted my rom to a stock MF9 rooted touchwiz rom, instructions and one click odin here:http://forum.xda-developers.com/show....php?t=2486134 I’m trying not to straight copy and paste someone else’s work so take a look at that post if you need a clean start. If you are coming from non stock you will need to boot into stock recovery and wipe data/cache before you get started. (I also later used SAC’s rom after a failed attempt at an AOKP fix and it worked as well ) you can switch to any ROM later and the unlock will stick.
2)I rebooted the phone and followed the instructions listed here in post #1 http://forum.xda-developers.com/show....php?t=2415587
3) I went to the dialer and typed *#0011# which brought me to the "service mode" Menu.
IF YOU HAVE TROUBLE GETTING THE HIDDEN MENU TO OPEN DO NOT FEAR! I had a ton of trouble at first. In some builds you need to activate an option by adding a line to your build.prop or changing the no flag in efs/hiddenmenu to ON. Google it, there is a ton of help out there.
4) Press the left menu softbutton (the menu button that lights up and vibrates when you touch it) then press the either the button “select” or “Key Input” and type the number 1 or 2 into the box, if nothing happens press menu and select the “back “ button then repeat. This app is sort of like a tin can radio, you can kind of tell that it’s working, but it doesn’t work well.
Depending on if you pressed 1 or 2 in the dialogue box it will take you into either an UMTS or CDMA menu. If you are in the umts menu, press the menu button and select back, this should then proceed to the next step.
5) Select CDMA, then 1.COMMON, press next page twice until you reach page three of COMMON and select 8.PREF MODE SET and select GSM_WCDMA_ONLY
6) Press menu and back until you are at the main menu and select UMTS, then select DEBUG SCREEN, then select PHONE CONTROL, select FAKE SECURITY CONTROL and make sure it is set to ON
7)Press menu and back and select  NAS CONTROL. We are going to check a few different settings in this menu so remember how to get here cause I don’t want to repeat myself.
 CIPHERING CONTROL = OFF
 INTEGRITY CONTROL =ON
 SIM CLASS CONTROL = UMTS
 REVISION CONTROL = DO NOT TOUCH
 RRC(HSPA) CONTROL = DO NOT TOUCH
 DUALMODE IMPROVEMENT CONTROL= DO NOT TOUCH
 NAS AVOID SECURITY CONTROL= OFF, 0
 BIP BLOCK = 1
8) Press menu and back twice, you should be on the PHONE CONTROL menu. Select  NETWORK CONTROL, select  GFC and make sure that it is set to GSM/(E)GPRS/WCDMA REL8 .
9) Press menu and back and select  BAND SELECTION and select WCDMA/GSM ALL for both WCDMA and GSM band preferences. I selected the ALL choice for LTE as well even though I know it isn’t supported for TMOBILE.
10) Under the NETWORK CONTROL menu we just came from select  AQUISITION ORDER and change it to UMTS_GSM
11) Press menu and back until you are in the PHONE CONTROL menu and select  SIMULATION , press the  SW WATCHDOG button 6(six) times and then the  HW WATCHDOG 6(six) times. Nothing will happen at all to let you know if you have done this correcctly but as soon as you finish the sixth press on HW WATCHDOG reboot the phone manually:manually:manually IMMEDIATELY . I’m not sure what this does or why this works but @nicotheandroidguy seems to have divined that this is the vital part of the process.
YOUR PHONE STILL WILL NOT HAVE DATA OR VOICE WHEN YOU REBOOT FROM THE WATCHDOG TAPS DO NOT PANIC!!!!!!!!!!! (hopefullly you have your towel with you)
12) WIFI that sonofa up and search for apn settings shortcut and build.prop editor in the Play Store.
Go into the build.prop editor and add the following two lines:
REBOOT PHONE MANUALLY now.
Now Install and create a shortcut on the home screen and select to open. Press the menu soft key and select add apn.
APN: epc.tmobile.com or fast.t-mobile.com (for LTE devices)
MMS protocol: WAP 2.0
APN type: default,supl,admin,dun,mms
13) Go into your android settings, select wireless networks, you should see the network mode set as wcdma only do not change this, we set this in the Service Mode Menu , Check that your roaming settings are set to for roaming data/ international data etc.also make sure that there are no roaming guards left on. (roaming guards will only allow you to uncheck GSM and GSM data under international roaming.)
At this point I had full access to the TMOBILE UMTS/HSPA+ network and voice/text/mms were working.
At this point you may change roms, be careful not to update past mf9 as you may be unable to downgrade to mdc. YOU MUST DOWNGRADE TO MDC MODEM FOR THIS TO WORK.
If you use a non touchwiz rom you can still access the tellinfo menu by pressing *#*#4636#*#* and selecting WCDMA only and manually adding the apn.
GOOD LUCK! let me know what needs changed in the guide as well.
If you have questions it's useful to know your Baseband /kernel/ rom.