Parasitic drag question

We are currently test flying an all fiber-glass experimental plane in an
unpainted state and wondered if any of you have done the same and
experienced as much as a 10% increase in air speed and improved climb rate
after painting your planes.
I know most of you are happy to wait until your pride and joy is painted but
we opted to test fly in the raw. The manufacturer who has a similar plane is
achieving around 10 knots better speed for the same revolutions, at 4,600
rpm on a Subaru conversion with a 2:1 reduction he gets 100 knots and we are
only just getting 90. The only difference in configuration is the addition
of front wheel fairing and three leg fairings plus nice shiny paint. Our
climb rate is also very low compared to predictions. It will be several
months before it is painted and back in the air so am asking the group.
Replies appreciated. Derek.