A good software remap is only as good as the cars hardware, it could blow up straight away after mapping or last 100,000+ miles without issues.
I have had cars go pop on the dyno during stock power runs even before mapping, I have had cars fail on test drive post mapping, but then 98% will never have issues.
TDIs are the worse as they run higher boost from stock and tuned, upto to 1.8bar is some cases, they also suffer from sticky VNT and slipping clutchs.
It rare for me to see a 1.8T with major issues, I had a around 4 cars spit on rods over the last 7 year, most common issue is smokey turbine seals on the turbo due to age and crap oils being used. I have 1.8T engine out there running 300bhp+ with 213k+ on the clocks.
At end of the day tuning is a risk, not with the mapping but the hardware.