Yes mate, that's me.. and No, I've never went through the car wash but I'd hate to see the damage it will cause.. *yikes*
Personally I really dont care how my car looks with a roof rack as long as it serves its purpose; and I use it every weekend.. abd best part about it is it literally takes only 15 seconds to secure my bike on the roof rack..
If you are really worried about wind-noise', Thule sells wind deflector - a plate that sits oin front of the roof rack and designed to deflect wind thus making it more aerodynamic I guess.. Wind noise were never an issue wiyth me though, I only heard it faintly on my golf, never bothered me with other cars I've owned. Also, If you are worried about fuel economy, I'd say roof racks will have much less drag than the rear bike carriers that sits the bikes horizontally across.
No idea what the sliding feature you talk of is.. one thing though, I wouldn't want my bike hanging off the boot secured only by a couple of straps.. I'm sure its all good but just for a peace of mind.