[Q] Just a little general help please - 7 Mozart General

Hi,
I was curious if i could install a custom rom on my phone, so i started searching for tutorials and guides. I've been looking for a couple of hours, but I'm quite confused and don't want to destroy my phone. I don't intend to spam, whatsoever here is the information:
OS Version: 7.10.7740.16
Firmware Revision Number: 2250.21.51101.111
Hardware Revision Number: 0004
Radio Sodtware Version: 5.71.09.02a_22.51.50.21U
Radio Hardware Version: A.102.0.D4
Bootloader Version: 5.11.2250.1(133065)
Chip SOC Version: 2.2.5.0
I wasn't sure what information is of importance. I hope that's everything you need to know. I aint lazy, I just got to work a lot and all this information is simply overwhelming. How do I know if my phone is branded? Do I have to downgrade the phone before I can install a ROM? Can I even downgrade this OS? Which ROM do I chose? ... Can someone please give me some links and a quick explanation what do I got to do and in which order?
Thanks alot in advance.

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Refer to your information, your ROM is
OS Version: 7.10.7740.16 --> WP 7.5 aka Mango
Firmware Revision Number: 2250.21.51101.111 --> for T-Mobile Germany
Hardware Revision Number: 0004 -- OK
Radio Sodtware Version: 5.71.09.02a_22.51.50.21U --> new bootloader version, you can upgrade directly to custom rom eith this bootloader.
Radio Hardware Version: A.102.0.D4 -- ok
Bootloader Version: 5.11.2250.1(133065) --- ok
Chip SOC Version: 2.2.5.0 -- ok
to debrand it,
1. unlock bootloader, refer to this thread
Code:
http://forum.xda-developers.com/showthread.php?t=1597837
2. Install Cotulla SPL
Code:
http://forum.xda-developers.com/showthread.php?t=1195647
3. Upgrade your ROM with one of here
Code:
http://forum.xda-developers.com/forumdisplay.php?f=786
hope it will help