Offtofly,
My 3W-75I used to drive my DA flying buddy absolutely crazy because it stumbled and growled and made all kinds of noises in the mid-range and I have to admit I kept it that way just to drive him nuts. Motor could climb with a DA 100 for the first 300 feet then the DA would leave me, but as soon as the motor hit 7 gallons and was fairly broken in I switch to 40:1 oil and tweeked the needles and now she midranges perfect. 6950 with a Biela 26x10 and 1100 idle with a crisp Bark on transition to full throttle.

Good Luck

JDS