If you are not very familiar with your device, I'd suggest you wait a while. But it's your choice. Yes, it will void the warranty, but if done properly, there should be no problems, and it is easy to downgrade the same. Gl either way.
what which option do i choose to install?
i want to make sure that when i install it, its legal and doesnt kill my warranty
The current situation is, Orange, a European carrier, has accepted OS v.4.5.0.52 for their network.
T-Mobile has not accepted it so far. They are still testing and perhaps correcting additional bug before they officially accept it.
Your warranty covers physical defects, not the system software.
You should be aware, asking for customer support with an unsupported OS is not going very far. You will be able ask questions here, but you will loose access to much of T-Mobile's support.
If you can wait, the official version will be released, but there is no time table published.
A little advice from an old computer geek, install your default v4.2.2.180 first. Once you are satisfied all is well, install the update. If anything goes wrong, all you have to do is remove the update and restore from your known good system.
If you ever have to return the device, you can roll it back and nobody would ever know the difference.