Can someone explain to me the animosity? why is everyone so instinctively butt-hurt? It's not like there is anything that shocking presented? can someone, instead of snarky comments, use words and explain why they are so offended?
Maybe it's because people have this wrong concept of mechanical failure where there is this magical HP number, where everything under it is hunky-dory safe, and everything over is immediately OMGWTF it's going to fall apart and brake. That's not how the world works, unless you are going to ridiculousness on either side. Ignore the shape of the curve, and the actual values, but the survival curve based on HP with stock internals assuming you don't have a retarded tune should look something like:
Note that this is % surviving. So are there 300whp engines that survive longer than stock engines? Most likely! Since up to whatever time point, it's not 100% failure, where as some stock engines start failing at low miles. Are there 500 whp engines that will survive longer than 350hp? sure. But I don't think it's necessarily economically wise to plan for a 300hp engine lasting 100,000 miles...
So the real question that only people with big pockets like subaru or maybe the big tuners know, is what the actual shape is at what hp level, and what are the components that brake, in order of likelyhood.
So if I understand properly, since FRS Justin has an n greater than 1, he believes in his personal experience, that it is the rods that break first, and if I understand him properly, he believes that the failure rate past 300-325 whp is uncomfortably high for his personal values.
If you are willing to take the risk and boost to 500whp, so be it, but I don't understand why you would be mad if someone told you that your engine PROBABLY will fail more quickly. And when it blows, don't assume it's the tune and would have been perfectly safe with a different tune.