Sounds like an IAG name. Properly built motors (and IAG does that well) are highly unlikely to blow up, but they have short lives in terms of wear. Say 60KMi of perfect operation and then slow reduction of compression and corresponding reduction of power and response. IAG was very up front with this when I built. Mines at app 75KMi?
I think general consensus is that EJs reliability decreases above 450AWHP (up from 400AWHP due to E85). This is mostly because cars at that level often have non-stock valve trains. I wouldn't take anything for granted. Even if it did produce 500AWHP on a dyno it may not be a great performing car. There is also a significant chance that the is not actually so near 500 awhp. It would be nice to see the build list and match it up with whats on the car.
Most importantly, if you are doing the maintenance on it, then you need to have a Subaru performance shop lined up to care for it.
Though you have provided precious little detail, I expect this is all the answer you need.