I used double sided tape to put the plexi on the car with. to be accurate, I used the kind that is weather proof that a lot of manufacturers use for their emblems. you can get it at autozone and similar places. buddy of mine told me about this but I didn't believe hime until he did it to his car and it seemed to work alright.
painted it and stuck it in place and it looked like crap. caulked it and well you see the results. ingenuity and a little "rigging" will get you a long ways.
Be the change you wish to see in the world