Maybe a better way to gauge this is to somehow compile engine failures and what exact part failed and under what conditions. A lot of boosted 86's here in Aus run street only.
I haven't heard of smashed gearboxes, so I think drive line is ok. Which basically leaves engine. Spun bearings are relatively common for this engine (suspected oil pump failure possibly) but I don't know that this has an relation to boosted cars. If anything boosted cars probably don't get revved as high and almost all run oil coolers. Actually come to think of it, I haven't even heard of any boosted cars failing other than crap tune or being totalled
. No stories of bent rods or anything.