Replace home DSL with 4G LTE

So recently T-Mobile upgraded their tower in my area. Before the upgrade, I was stuck on 2G, but now I'm getting 20Mbps up and down on 4G LTE. Right now we pay about $50 a month for shitty 3Mbps DSL. T-Mobile offers an unlimited data plan for $80 a month, with a 5 or 6 GB tether limit. However, you can go over that limit using USB tethering on a rooted device. I've tested it with the plan I'm on (only 100MB tethering) and I easly hit 500MB with no problem. I've also read that plenty of people use hundreds of GB through tethering without T-Mobile saying a word (my family uses around 20-40GB a month). I've also read that using a VPN and User Agent Switcher makes it really difficult for T-Mobile to know if you are using tethering or not. I plan on using my router as a wireless repeater and having my phone connect to a VPN. What do you guys think? Am I better off paying a stupid amount of money for crap service that continues to get worse month after month, or is this an OK idea?

When I was in my dorms I used 500gb/mo ish sometimes more off my phone because the dorm internet was shit.

I would see about getting a crap phone that can at least handle the LTE speed, root it, then just have it constantly tethered directly with a router that has that sort of functionality such as the one I'm using, the Asus RT-AC68P. You'll notice at the bottom of the page 3G/4G data sharing. In reality you can basically just set the WAN to the 4G device to begin with.

You could even schedule spoof phone calls and texts to fly more under the radar.

Interesting...I tried to install an update on my PC (big download) and tethering shut off every few seconds. I used User Agent Switcher to make it think that I was using a Android browser, and the tethering stayed up. I tried using a VPN while downloading the update, and the connection shut off again. Maybe I need to set up the VPN on my phone too?

I don't have a USB capable router. I was thinking of just running the connection through my PC to the router until I can afford one.

pfsense is your friend. however, i would like to mention that given the way these companies are moving the unlimited tethering thing could be removed in the future leaving you with your pants down. if i were in your shoes id setup a pfsense box and have it connect to both the dsl and a tethered phone and use the crap out of it. the benefit being that if tmobile "fixes" the issue u will simply unplug the phone and toss it and you will learn a lot about how the internet is setup.

I have a pfsense box that I don't use because of a faulty ethernet card, but keeping both the DSL and T Mobile would be a bit too expensive.

I used that before I installed Cyanogenmod. I just use the default tethering app for Cyanogenmod and have gone way over the 100MB cap on my 5GB plan. No slow downs so far. Some applications don't work on Windows (I.E. GTAV, Steam, etc.), but everything I have on Linux works fine