I think all aftermarket S2000 exhausts have that drone... dependent on how loud the drone is varies from exhaust companies.

I find if you hold the V3 at 5500rpm, its dead silent, but as soon as it moves either way, esp into vtec, its exceptionally loud.
100km/h about 4000rpm, drone, no matter what.... I'm used to it though.

You can use body deadener to decrease the drone sound though.