Well the Miata is a bit of an unusual example, I admit, because it's based on an engine that in a previous incarnation was turbocharged. So it's already built to take some boost. But, the point I was trying to make is that you can't just use a blanket statement like "you need this and that and the other if you're going to turbo a car".
As for longevity.... the engine already had 150,000 miles on it when it was turbo'd, and it was not in the best shape ever. It's now had the living shit kicked out of it on a daily basis (he doesn't even wait for it to warm up before giving it), for coming up for 3 years and another 30,000 miles, and it's still making 260whp, based on a recent dyno. It's not had a single mechanical issue since putting the turbo. However, it is a DECENT turbo setup from
www.flyinmiata.net that has also been properly tuned, not a crappy home built kit built with little consideration and tuned by someone without a clue, so ymmv :P