Hey Myke,
I myself just picked up a 2016 FiST, I did some extensive research and like you found the coolant and clutch problem with the 15's. I didn't find anything alarming with the 16's however. I say test drive the vehicle, give it a good looking over, let the salesman know about your concerns, and don't be rushed and let the excitement influence your purchase. It may cause you to overlook things. I've had great cars come from Private Sellers and Crappy Lemons come from Certified Dealers. So just take your time and if it's a deal. DO IT!
I myself just picked up a 2016 FiST, I did some extensive research and like you found the coolant and clutch problem with the 15's. I didn't find anything alarming with the 16's however. I say test drive the vehicle, give it a good looking over, let the salesman know about your concerns, and don't be rushed and let the excitement influence your purchase. It may cause you to overlook things. I've had great cars come from Private Sellers and Crappy Lemons come from Certified Dealers. So just take your time and if it's a deal. DO IT!