What bands do you want to monitor in your Blackwood?
And what kind of gain are you interested in? The more "low profile" you want to be cuts into the amount of gain you are going to get.
You won't need much gain if you're talking about UHF or 800 repeater/trunking systems that you are in the midst of.
You are going to need a lot of gain if you're talking VHF low or high, or comms that you are many miles from.
(Nice car, btw)