I've owned my V-Spec for two years and just recently needed to replace the piston & sleeve (worn out from use). So I replaced them with the JP modified p/s and rod. So far it performs good, much better than a worn out engine LOL but I can't claim any fantastic power increase (if there is any) or if it will last longer (racing engines tend to have shorter life spans) but it was cheaper than buying the OS parts.
BTW: My engine still has the original bearings and they look in great shape. Now I only wish that the price of those P3 plugs would come down a bit.