Nah, I think you have me wrong - What I mean about lack of air is with the piston FULLY pushed in. Pull the shaft out and it will suck back in to some degree. No problem at all with full compression - thats the lack of air I am talking about (vacum).
5mm of extension on full compression is more than none - so you are getting an effect (no matter how small) - more so than no effect at all.
The slowing of the piston at the end (more than the 'pack can acheive') would only come into play on the heaviest of landings - so would have no effect on the general handling of the car. *as I understand it
