I am planning to change the wheels on my KOUP SX when I get it to XXR 517 17x7 wheels. Not changing the tires just the wheels. Would I need to buy four new TPMS valve stems or can the ones that came with the factory rims be used with no problem?
Well, I would hesitate to say "with no problems" but it should be doable. The TPMS are not a permanent mount, but they are fragile - so much so that we simply do not do this in our shop. Ever.
We get requests twice a year from a whole bunch of people who want their sensors swapped from their winters to their summers and it's just not worth the $200+ each in case a mistake is made. We've even seen them go dead from no obvious cause at all.
It's possible, and your tire shop should be able to manage it... if not it's their dime if they break one. As your car is fairly new, at least the threads won't be corroded, or otherwise... that really can make a huge difference.