Originally Posted by GaryJG

I would prefer the 350. Carbon build up will probably happen to both engines, but the turbos usually have alot more other worries down the road...

For starters, the design of a turbocharger: It has to work at extreme temperatures of hot exhaust gases, while the turbocharger shaft is lubricated by engine oil. This means there is more demand to the oil quality. Engine oil deteriorates faster under extreme heat. A turbocharged engine will not forgive low oil level, poor-quality oil or extended intervals between oil changes. Most turbocharged cars need high-quality synthetic oil and have shorter maintenance intervals. Some also require premium gasoline.

Turbo engines tend to have more problems in many cars, although there are turbocharged engines that are reliable. A turbocharged engine has more components than a naturally-aspirated (non-turbo) motor. These include an exhaust wastegate setup, intercooler, boost control system, vacuum pump and a more complicated crankcase ventilation (PCV). A turbocharger itself is not uncommon to fail. The more parts, the more can go wrong.

At higher mileage, as the cylinder walls and pistons rings wear out, higher combustion chamber pressure results in increased pressure inside the engine crankcase. This can result in oil leaks that pop up from many places and are difficult to fix.