I had a 981 Cayman GTS that I traded for a 981 GT4, which I currently have. My girlfriend had a 718 base Cayman and currently has a Cayman T. My GT4 was purchased in January 2018 as a CPO with 765 miles on it and currently has 8100 miles on it. I do 2000 miles a year basically and all those miles are in the mountains or spirited drives. I'm fortunate to live near fun roads and I'm close to some epic roads.
I've installed Dundon Race Headers, Dundon tune, and purchased some GiroDisc iron rotors to run to preserve the ceramic brakes.
My FiST was purchased as a leftover 2017 in late 2018. It has 32000 miles on it. It gets used for groceries, commuting, mountain runs, and it's my primary track car. On the FiST I have done air intake, Fortune Auto 500s, two sets of OZ wheels, Cobb AP, RMM, three sets of rotors/pads, and have the M-Factory LSD still to install. Also a few other things here and there.
I've done more to the FiST but spent close to the same amount of money. And the GT4 is still the more competent car. A Cayman is always going to be a more competent car. Even out of the box, the Cayman T is more competent. It carries the speed better, corners better, it's mid-engine, it's better balanced, it has considerably larger rubber, it brakes better, has better clutch feel, better steering feel, and better brake feel. If you're giving up a Cayman or Boxster for a Fiesta ST it's not because it's better. It's because it's more fun. It's also less expensive, less worrisome, seats more people, and provides a different type of engagement.
I've shared this several times, that I also ride motorcycles. I have a 2017 BMW S1000RR. It's the most insane thing I've ever owned. It's arguably one of the best super sport bikes made. I also have a Honda Grom. The Grom is the more fun bike to ride. And it barely does 55 mph. It's 0-60 in never. But it's an absolute blast.
That's the Fiesta ST. It's a blast. It engaging and fun and genuinaly is a laugh to drive hard. And yes, with enough money and the right driver, can be made to run with Porsches.