best speaker placement for car with strip

So I'm going to running a stripped interior (everything but seats; no dash) as this is going to be a autocross car (86 Mustang Coupe), however it will be driven to and from the track and I need some tunes along the way.

I will be using heat/sound barrier on the firewall and roof but thats it. The trunk area will not be closed in with the rear seat or rear deck cover. I know this is not even close to being a good environment for the stereo, but its what I got.

I have CDT components, 2 8" CDT subs and a Kenwood amp and deck. Since the interior is gone I can mount the speakers just about anywhere.

What would be the best placement for the mids and tweeters. I know the tweets should be at ear level, how about the mids? Also since the truck area is open which direction is best for the subs to face? I would say facing up like a hatch back.

Thanks!

Heres a pic of the setup: