My grille has a sliding block, though it only slides ~10mm because of the power lock motor I used. If you use a cable, then the openings can be wider, allowing freer airflow and/or partial opening.
The only problem I have with it is when I park during a snowstorm and the snow melts on the warm hood, then freezes while dripping down the grille. Ice forms on the outside and in between the sliding elements, blocking them. Of course, this happens only when it is cold, and then I don't need to open the grille often (plus the radiator's heat might melt the ice if it gets hot).
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e·co·mod·ding: the art of turning vehicles into what they should be
What matters is
where you're going, not
how fast.
"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell
[Old] Piwoslaw's Peugeot 307sw modding thread