Is Bradthemad's antenna set-up too much for you, or is that okay? That's about the ideal antenna size for a good balance of performance and aesthetics.
There are a lot of different kinds of NMO mounts. The problems with trunk lip mounts are:
1. taking it on and off affects your SWRs, meaning you need to re-test it every time you do so.Magnetic mounts have the same problems, but are less susceptible to SWR problems, so long as your placement is consistent. They're also a lot easier to move. The loose coax looks bad though.
2. They're often kind of big and gaudy looking
3. They often induce more noise than other kinds of mounts.
Trunk groove mounts are a good in-between option that avoid SWR and noise problems, look a little better, and still allow for trouble free removal.
If you can bring yourself to do it, drilling a hole like Brad did is very much the best way to go, all around.