Great idea looking forward to seeing it come together.
What about using a 4 door so you will be in a much lower starting price point and make it more police car like with a rear cage to transport criminals and all.
If you keep your eyes peeled I have seen cherry right out of granny's garage examples less than 5K. The same cars pop out from time to time in 2 dr versions 15-20K just some food for thought.