Originally Posted by michal12

Well I think 4.8iS and E70 4.8i are two completely different engines. While the iS engine is an evolution of 4.6iS developed for BMW by Alpina(!) and has been produced in very low volumes and for E53 only, the E70 4.8i is the standard BMW engine from 750i which has been developed inhouse from 4.4 and is being produced in larger volumes.
Of course, the exhaust system is different too as the 4.8iS was a semi "M" model with more agressive note.