What is the biggest motor you can put in a 1996 audi a6 with a 2.8 in it?

just wondering what i could put in if it goesWhat is the biggest motor you can put in a 1996 audi a6 with a 2.8 in it?Even if you were to put the V8 in it, you still need the gearbox and assorted electronics, since it came from an A8. Not worth the effort.What is the biggest motor you can put in a 1996 audi a6 with a 2.8 in it?4.3 V8 fits straight in has up to 500BHP,but cheaper to buy an S6