The wheel pants should give you a couple of knots. Flap gap seals would give you a knot or two. Knots2U makes great products; I've used them on a half dozen aircraft. Good luck!
Wright Brothers Master Pilot, FAA Commercial Pilot
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I installed the gap seals, along with the nose wheel pant, in my 1979 172N about 15 years ago. There was not any noticeable increase in cruise speed. The complete set of wheel pants makes a difference of about 3 knots. The biggest difference came from the PowerFlow Exhaust. In its prime, the plane would cruise a little above book speed, 124 knots, at 7500 ft, rich of peak.
Thanks Egon, good to know.