A police radio interceptor (scanner) - Would be a neat little feature that could be useful for criminals on the server. This feature would allow criminals to intercept communications between cops, with this item being purchasable from the black market (maybe weapon dealers, when they're added). This would mean cops, would need to be very careful on what they say in cop radio, and could also add in a little feature where it allows criminals to see cops on the radar. Even if they're using the cia/fbi/swat skins that have lower visibility.
This item would be a limited item, where it takes 2 - 3 game days for stock to replenish if you're arrested it gets confiscated. Purchase price, could be around $10,000? or depending on what happens response wise to this post, maybe lower... maybe higher.
Just some food for thought.