How about adding 4 cylinders?
I like the cut of your jib.
Really, though, I think any steps taken solely to alter or amplify the sound the of the engines would be just as artificial as DRS, mandatory tire compound use, and all the other nonsense that's popped up lately. And this is coming from someone who absolutely abhors the exhaust note of the new power units.
At what point do these sorts of machinations become an insulting caricature of a sport more interested in trading on its legacy than building upon it? (Are we there yet?)
Besides, what made the sound of the previous engines truly special was the way in which it was created. Any sound can be synthesized. But, would you rather hear the sound of a high-rev engine screaming around a circuit or would you rather hear an actual high-rev engine screaming around a circuit?
Sometimes I'm embarrassed to be a Formula One fan. EDIT: Well, not really. But, I do often question why I'm a fan.