While I would agree with your 402 suggestion, L_R_T, the idea that GTSIO engines almost never make TBO is completely dependant on the operator/pilots.
Service history has found that, if handled with the very necessary care and attention these engines deserve, they have proven to be very reliable in service, and can indeed be expected to reach TBO.
Recent problems with the starter adapter/dampers, notwithstanding...
Also, keep in mind that TSIO520 engines have counterweights as well, with the same cautions advised.