I know 4 tuned Turbos, three with 543 HP and one with 569 HP.
One car is a Tip and got the Tiptronic replaced after 50000 km of "tuned" driving! Not bad, eh?!
The other three have 35000-70000 km on them WITH the tuned engines and NO problems so far. No kidding.
I also know a 5th car with 543 HP and it has tuned 16000 km (10000 km with 500 HP and 6000 km with 543 HP) with no problems at all.
It is very important WHO does the Tuning and HOW he does it. Power is not always power, it depends how this power has been obtained and what compromise has been made.
If you're expecting reliable 100000 km+ out of a tuned 570 HP monster, forget it. But if it is done right, at least 50000 km shouldn't be a problem without major problems.
VERY important: change engine oil/gearbox oil more often, including the oil filter. A sport clutch is mandatory (not only clutch disc but pressure plate too). Serious track racing should be avoided, especially with so called semi-slicks. For track racing, reducing weight might be a better way.
ANY problem should be looked into it immediately and immediate repairs are mandatory to avoid destroying more.
BTW: stage 3 is just fine, especially regarding cost and reliability.
If your car is your daily driver and you depend on it, you might not want to tune it at all.