Naaaw, bifurcated pipes sound like vaccum cleaners. The sound of two unpiped engines is amazing. As to the "synced": you will always have slight deviation in rpm, therefore having them sing anyway...

Well, you can argue reliability of single engine, but when one goes down, you have yourself a flying rock (remember, gliding distance of your plane is always half of the distance back to the field...). You can turn that argumentation around any way you want it...

There is never a better way, theres always just a bunch of opinions