i have a thing about using engine additives just for that bit more protection i suppose as i run lpgas. can't sy anything bad against them as i have never had any problems.
found one today at motormate (SA ) called RESTORE OR ENGINE RESTORE have checked this on the internet and their are mainly good and some bad reports . so i decided to give it a go ($40)as the old vp has done 300,000klm. its suppose to recoat worn surfaces , increasing compression, quieting motor etc. well i must say it actually works my v6 is quieter ,smoother and definitely has increased performance. were not talking lots of kw just enough to notice. apparently it brings old motors back close to original performance.
at this stage i am quite happy didn't realise how tired the old motor was.