I thought about this question pretty long. I've had my '16 GTI since it was new, and it's all kinds of fun to drive (minus the rubbish OEM Bridgestone Potenzas, which are getting nixed today or tomorrow finally). I always felt like it had "enough" power stock. I currently have about 14k miles on it.
Nevertheless, the bug kept on biting on what I knew a Stage 1+ Unitronics tune would do for the car. So I finally made the purchase from ModdedEuros and my Uniconnect should arrive next week for the Stage 1+ & TCU flashes.
I obviously haven't run out my powertrain warranty yet, and that did play in. Nevertheless, a few things factored into me taking the plunge despite the warranty questions:
1) It's my daily driver, but I also live in Chicago, so I have tons of public transit options if I kill my car. I don't need my car to get to work, and it's pretty low miles considering it's now going on three years old.
2) I wasn't able to find a single instance where a Unitronic Stage 1+ & TCU tune killed a motor or DSG, mechanically or ECU (and it sounds like Unitronic has processes to help if you do happen to have a bad flash).
3) I haven't read anything about the MQB motor having any sort of intrinsic problems that a tune might accelerate. Everything I've read seems to indicate this motor is a tank. All VW criticisms aside, historically I think they've made great motors (I had a MK3 Jetta years ago that, while the manual tranny self-machined itself to death like all those riveted trannies did back then, the motor itself was an absolute tank. I chipped that Jetta back when it was an actual chip you could install
).
4) I have a local Unitronic dealer that also has a very good rep for VW tuning and repairs, so I know that even if I do have to pay out of pocket because something is broken and not covered by warranty, there is a good shop other than the stealerships that can help me out.
I'm pretty confident that I won't have issues with this tune once it's installed. I'll post my thoughts some time next week after I do the flashes.