Pikey -
Yes but we're not talking about out and out race cars.
At the end of the day it's a Golf Mk5. Not a Caterham. If a car is 1380 kg or 1360kg you are
not going to notice. You can be all about the "theoretical" improvements if you want but the truth is you're not going to notice a 20kg difference over the rear axle of a Golf.
Maybe people at the track who would laugh do so because they have no idea what air actually drives like. Like yourself
Karl -
You are right, you can have more issues with air bags. However the airbags themselves are more durable than a regular coilover, if you look at a coilover unit after 2 years on a car and then an air suspension unit, the air unit would be in a better condition.
As I'm sure you're aware, buses, lorries, trucks, and some vans now are coming with air suspension and these vehicles do hundreds of thousands of miles. At wheels day there was an old Ford hot-rod which was on a 18 year old air suspension system.
I know of a TT running 10 year old Rayvern air suspension and the components were fine there was only one small air leak TANK SIDE (so not from the air bags themselves).
You can still get a snapped spring on a coilover and you'd be in exactly the same situation.
The air lift bags are valved to work without a roll bar so that's irrelevant. You can get Performance Airlift struts which have drop link mounts for a rollbar as well - the whole "you don't have a rollbar" argument is a bit old and pointless!
There is also great discussion on what the true benefits of an anti roll bar are, as you are in effect taking your 4 independant suspension units and making them not independent.
McLaren MP4-12c doesn't have any rollbars at all.... neither does the P1...