I'm really happy with this add-on. It's great overall, but one thing I noticed is the sideslip behavior. I am not 100% sure how the real PA28 behaves on that behalf but what I know from other aircrafts is, that usually they drop like a stone without speed increase. The JF PA28 doesn't seem to simulate that correctly.
If I am correct on this, it would be huge if it could be patched. It would add a lot to the realism. Especially on X-Plane which usually depicts aerodynamic influences on the plane quite well.