[razordave]

I believe the bulges on the car in the video are from the wings? If I were to find the facilities to pull this off, I would either widen the airplane body to gradually taper the needed width for the rear axle or shorten said axle and tuck it up inside.

I have been looking at abs diffusers on ebay..

$30 for 22x20 building base..

I was going to cut my bumper and run the exhaust straight through where the reverse light used to be but I ended up with a 90 bend and a turn down directly behind the driver rear tire.

Probably better for noise mitigation and smoke dissipation.