There really are no good solutions for these newer toy
cars. That's why I don't have an antenna on my Corolla
even 3-4 years after I bought it. :/ Not even a 2m whip.
I had an Accord before the Corolla, and I drilled a
hole in the trunk and reinforced it with plates under
the trunk. It still distorted the thin metal of the trunk
after a while. My antennas are tall, and I *will* hit
something sooner or later. Usually trees.. But even the
lower stress of highway speed wind will distort one after
a while. The bike racks can be used, but you would have to
search long and hard to find a worse place to mount an
antenna. The ground losses will be much greater than any
antenna mounted up on the car. I don't care how well it's
grounded via wires.. The wire grounding scheme with little
metal under the base of the antenna just doesn't get it done.
It will be a good DC ground, but a **** poor RF ground.
Expect performance to basically suck..
So... I've pretty much given up trying to mount an antenna
on that car. It will end up trashing my car, and being as it's
still fairly pristine, I'm not willing to do it.
I've still got my old trucks if I really have to have a radio
and antenna. They have antenna mounts which work well and
never a concern about warping metal. I just have to cough up
lots more for gas.
When I drive up to my place in OK, it's a 900 mile round trip,
and I drive the car to save gas. I just go without a radio until
I get there. I have dipoles in the trees there, with 100 ft of
coax that I keep rolled up on a tree branch stump. I miss the
radio on the drive, but not enough to butcher up my car. :/