hardened valves, guides and seats - will overcome most concernes from LRP - issues with detonation can be addressed by mostly modded timing and/or going to EFI or even simple water injection.
edit: as for conspiracy theory about LRP ? ! they use MTBE and a few other nasty chemicals that probably give you cancer.. but odds are that you'll die in a traffic accident or from cigaretes (intentional or not) way before the petrol gets you...