read the uhaul literature on towing low clearance cars. It is not covered by their warranty but pretty easy to manage. Use the 2x8x8's cut to various lengths including the front of the trailer where the wheels are strapped. Towed my 2005 elise from boston to nj with no problems.
with the elise the weight was not a problem, just needed to use boards under the tires in the front of the trailer to make sure the front clam cleared the front of the trailer! overall the balance seemed pretty good.