IMO some R500 owners and prospective new owners are not understanding what a top end refresh is. A refresh is a head off job , lap in the valves, clean and reassembly fit new valve springs, reshim the cams/followers. As this work is confined to the top end of the engine and with the exception of the new valve springs will do little to extend the life of the whole engine from a engine failure point of view, its aim is to maintain performance through maintaining compression and ensuring that valve clearances are maintained. Most R500 engine failures are failures due to problems with lubrication causing con rod failure, this can be down to incorrect assembly, worn big end or main bearings, owners not keeping their oil topped up , over revving on downshifts, working the engine hard before the oil and water are at normal operating temp etc etc.