Generally a resonator is used to affect the resonance of the exhaust sound and a muffler to muffle or quite it down. The question is, does the engine create any unpleasant frequencies in its normal operating range. The short answer for the M62 is "not really". My 540 has hollowed out cats (they fell apart, the car is driven less than 2k miles per year so I just cleaned them out) and a muffler delete. Resonator still in place. I think it sounds great, very low rumble under partial load, snappy when revving in neutral, was a daily driver for some time in this state and never made me wish it was any different. With separate pipes for each bank you're going to introduce a lot more lumpiness to the sound since the two banks wont have a chance to balance each other before exiting into atmosphere. However again because the M62 is not offensive even with dumped headers (I've tried it for S&Gs) you should be fine. ALL THAT SAID, sound is a personal preference so what one likes another may not. . .

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Again Daily Driven SC'd 4.6iS, whats the point of having a sweet ride if you dont use it all the time.