Dented LE tells there is not enough pressure inside. The older/more used the kite (esp. Speed) is, the worst this phenomena gets
Foil kites just start to leak at some point too much. With paragliders they keep record of the flying hours and measure the air tightness of the fabric - when certain limits are passed glider is not airworthy any more.
Leaking fabric causes general problems for the kite: it makes kite soft, wobbly, slow, folds wingtips etc., it adds drag. Very bad effects.
If problems started after the "accident" I suspect there is also a tear somewhere, even though a small tear is not very harmful for the flying of the foil kite. Added with previous leaks it may be too much.
FS air intakes are simple and work very well, I haven''t heard any problems with them.
Read foilholio's post about recoating foil kites, he can give you help for the mixer adjustments too.