I have a Thule 9103. Works pretty good for me, and it fits in the boot of my Polo If I do go for a long drive (2 hours plus) I just remove the seat post and wheels to minimize the impact on fuel consumption (29ers have some big ass wheels!). You make a good point about theft though. I do lock the bikes to the rack itself to ward of most would be thiefs. But like you said, a determined thief could cut the top straps (they are metal right?). But for that matter they could also cut the cable lock? The bottom clips look like the will only come out if the boot is open... unless you bend the boot where it clips in Damn, I hope they don't try that with my car! If I do have to leave the bikes on the car, I just try and park where I can see the car, or where there are lots of people that would notice if someone is cutting up my bike rack. Don't think there is a perfect solution if you don't want to use tow bar mounted racks (btw... took me a while to figure out what "two bar mounted racks" are ).
