I too would like to see some thin but tough (and yet easily removable) underbody panels to protect all those exposed important bits under the car.
I know you'll appreciate the can of worms you've opened up for yourselves as engineers, but hey, if you do manage to get really really close to satisfying the outlandish demands of your customer (us), kudos to you.
Oh, and how about a 4 litre flat six that fits in a 986 engine bay?