It ain't free. You pay for it, with increased combustion chamber pressures, over time. Turbo oil seals go out, flood your plenum with oil (which doesn't combust- makes black smoke out your exhaust), water-to-air intercoolers go out , just like a heater core can go out, and flood your plenum with coolant - which doesn't combust (makes white smoke out your exhaust) - and smells like burning syrup...
Turbos on what I work on now are $3k to replace, because they're all manufactured "as a unit" and you can't rebuild them.
Lift a head? Too much boost pressure blows out head gaskets. Have fun replacing head gaskets on the engine with a turbo. Just to get to them, you'll be replacing ALOT MORE gaskets, just for the head gaskets that lifted - from too much pressure.
It happens. Turbos happen. They're fun, when they work - until they don't work anymore.
Old skool topend shiit, 2-strokes. I can rebuild a 2-stroke topend for around $400. If I'm rebuilding the same 4-stroke topend, it's $2k minimum. Add a turbo on that thing, and multiply the repair by 3x... It's gonna be AT LEAST $6k to rebuild a turbo 4-stroke engine. And that's just scratching the surface. Need to see the damage first, but that's just the minimum. If you fucked up the bottom end, too - we're $8k minimum. Just to rebuild it.
There is not one thing about horsepower, that's "free." Ever. The more horsepower you have, the more money it will cost you when you need to rebuild it. And that rebuild is coming, always, trust me.
Then, what do I know about this stuff... Not like I rebuilt a Turbo engine 3 weeks ago, and just replaced an entire engine last week - because it was cheaper to put a crate engine in it, than rebuild the damage that was there... But, whatever... I don't know shiit...