Hey,
I've designed this kit to convert your Ultima into a mid-motor buggy.
It is shown here with the roll-cage, I designed but works also with the original body set. Furthermore it is compatible with the turbo and rerelease chassis, and ultima2 and ultima pro chassis.
(The ultima pro-xl rear arms are not compatible.)
Other parts in the image include the shorty holder kit, adjustable wing-mount, wide front-end kit and ED-special bumper.
front page illustration by
scratch_ed, on Flickr
The kit parts are all available in my shapeways shop.