Well this was all super helpful! (except for @
veganbikes haha)
I ended up buying from planetcyclery.com: 2 GP 5000 tires for $89.98 total. That is almost half the price they would've been from the LBS. Plus, they shipped with OnTrac ground which was free and they showed up the next day (from Denver, CO to me in Provo, UT). They seem legit to me, but only the test of time will tell.