I put mine inside my center console. There was a molded spot inside on my 2001 that looked like it was a place where they might have put a cigarette lighter. It was a perfect flat surface and hid it which I prefer. Don't want anyone knowing I have that in CA lol.
There is not a better spot IMO, I put mine there and nobody knows it's there, not even the passenger can see when you flip it open to turn it up.
Key lock on mine as well, only way I'd go. Most people think it's some kind of security system.
You would have 5 tunes and you can remove the key in position 1,3,5.
You can choose 5 different tunes of you liking. If you want a valet tune or a no start tune you must have it in one of the positions you can remove the key to be effective.