First off will be a lightweight splitter for the cars - I have a temp. plywood item but it weighs too much. I'm thinking - use a 10mm foam core (whats the lightest foamboard that wont react?), but then is simply laying  carbon/kevlar sheet/resin on top of this sufficient? I'm not really in it for the looks, just weight/strength. Any suggestions/links/instructions for me here would be good