The STI was manual? Auto would not allow operating condition out of the set parameters. So any kind of damage would most likely come from ripping it at red line.Let me put it this way: I spun a bearing on my STI engine from driving at high load/low RPM/high gear. I only drive this car in sport mode now after trying smart for a couple weeks and observing the behavior. Less than 2000 RPM cruising in 7th on the highway and giving it a little gas to accelerate a bit from time to time resulting in no downshift made me very nervous. I know there's a long warranty on these vehicles and it's one of the main reasons I bought it but if I can avoid having the engine replaced just by changing the driving mode I would rather do that than have extended downtime.
There is absolutely no reason for excessive downshift when your generating 510nm of torque at a near idle 1300rpm