Its too bad Superdave didn't get the same results as some other 180/185 owners, is it possible he is looking at indicated and not calculating TAS???
I have a 55 180 with 8.50/6.00's and I put the Snider speed kit on, (no wheelpants) after I put in a PPonk O-520. I flew it without the kit for about 50 hours. I gained 10 knots with the engine alone, 150 knots TRUE up high, not to mention the increadable climb rate.
The speed kit gave me another 10 knots,....BUT I also was a little disapointed at first. I was flying home at 4500' and only saw 5 mph indicated. But you must remember the advertised airspeed increases are TRUE AIRSPEED, NOT INDICATED. I climbed to 7500' standard OAT, and saw 160 knots, TRUE AIRSPEED. I calculated it 3 times thinking I screwed up my math. Nope, 160 TAS, throttle wide open, 2500rpm, 14gph.
Flying back from LA at 10,500 a C-182RG was only 5 knots faster in trail!
I have since put about 150 hours on it and I consisently have to power back early in a descent. I always check my true airspeed and it is consistent. The higher you go the more you will notice the difference it makes to clean up the gear.
Would I do it again???? Hell yes!!!! The best $2500 I spent just behind the engine.
Rich