Mike
When I say unstable I don't mean to the point that it is uncontrollable, it just takes some of the stability away to increase roll rate. Straight and level the Harrier is still stable and tracks perfect, just in the roll it a lot more sensitive, with reduced aileron throw it handles great. Once I start a turn I find that I hold opposite aileron through the turn, then add even more aileron to straighten out to level flight. Adding a gyro may work but I want to keep it as simple as possible.