who cares where they come from if they work, i,ve lost count of the number of n1 pumps i've heard of failing within 1000kms, nitto pumps have been out long enough now for us to hear about them failing.
just read that thread in the uk, it had only done 625km and looks like it had other issues that caused the failure.
been limiter bashing(7500) mine for three years now, hope it holds out for another three.
my car only gets driven at drift events and makes just over 300 rwkw. my first build lasted 18 months before a aggressive tune blew a head gasket and pitted the pistons. that was about 18 months ago and the new egine is still running great and i run it on e85 so it should't ping again. i'm a bit like you though, can't decide if i should pull it down and check it out or wait till it wears out?