the fact of the matter is simple, it can and will fail soon
the mean time between failure is rapidly advancing on 15 year turbochargers.
if you can afford to rebuild it keep going and dont worry
if you cant and dont want to fork out the 5 or 6k to rebuild it and buy new turbochargers then replace the stockers now. either with oem steel wheelies, larger steel wheelies or some other bolt on stock-er-look-a-likes
but for god sakes, dont keep going thinking it wont fail, cos it will
and when it does, youll be upset cos it will be rebuild time
we dont care that you are making xyz on zyx boost or xzy on stock turbo's
but you need to know that its a timebomb and youll regret it when it fails, unless you have unlimited money