Buying advice Hot Hatch. Polo Gti or Corsa E OPC

Hello Forengemeinde, After I was already well advised in terms of purchase decision is now a new topic. A sporty fast car has to come here, I know, there are many different advocates and warehouses here. At the moment I love with the Polo GTI from year 2015 with 1.8 machine or the Opel Corsa E OPC. Budget goes up to 18k € There you get something reasonable. I haven’t heard much where the weak points of these cars lie, neither to the Polo nor Corsa much more serious read and hope to hear some advice or even a tip in a completely different direction from other manufacturers. A purchase decision is always very lengthy with me, I want to save myself the grip in the toilet as much as possible I thank you now for your help.