Get another resonator fitted to your exhaust, and it should solve the problem.
When my car was NA, I had two resonators and the rear muffler, it may sound like overkill, but the car sounded bloody smooth. When the extractors where fitted, it did sound a little "throatier", but you'd have to know the car pretty well to tell any difference.
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For sale: Cobe Extractors to Suit RB25/20DE - $200