Nope, never had an issue. Alas, that Mini is no more. On my current MPi, I wanted to do the same thing but unfortunately the bodyshop doing the light resto drilled the holes in the doors in slightly the wrong place so I couldn't use them this time. Instead, I fitted grommets in the hols on the body and door, then used black heat shrink on the speaker wires where they'd be exposed. The cables were a snug fit in the grommets and seeing as the wires are a lot thinner than the gaiters I used previously, it really is very discreet and unnoticeable.
https://www.dropbox....C_0703.JPG?dl=0
https://www.dropbox....C_0705.JPG?dl=0