The turbo doesn't add much more complexity, but it has meaningful impact on other engine components.
It does create more stress on the engine itself - the only way you can get more power and torque from a smaller displacement engine is by significantly increasing combustion pressure and temperature, and consequently the load on bearings, cylinder walls, etc. Of course, these components can be designed to withstand these higher loads, but there is no free lunch, there will always be a trade off between how much power you can squeeze out of a certain displacement and engine longevity.
Turbos also introduce more stress on the oil. The oil is subject to higher temperatures when it is used to cool and lubricate the turbo, and the engine in general. It's a bit of a contradiction game, as you need very thin oil to lubricate a fast spinning turbo, and you want a thicker oil to lubricate the crankshaft bearing which are now subject higher loads / pressures.
Only time will tell how good of a balance between performance, longevity and cost did Toyota strike with these new engines. The Tundra engine debacle doesn't look good, but the T24A has been relatively trouble-free so far.
Personally, I don't expect the T24A engines to last as long as some of the best older large displacement Toyota engines. But it may prove itself to be sufficiently reliable and durable for most of people. I never keep cars beyond 100k miles (with one notable exception but that was when I was a poor college student), so I am not overly worried. But it may hit resale value or those owners who like to keep their cars "until the wheels fall off".
www.tundras.com
