Wheels and disc rotors were a massive weight saving from memory. Unfortunately all the weights and photos were lost when the Australian and Singapore Copen sites went down I went with Take-Off CRF-08 magnesium alloy wheels (~3kg each) and two piece Take-Off rotors (alu bells with slotted rotors). Car handling and responsiveness was transformed. The carbon Bride seats also helped.
I'm doing some wheel research, think I figured out the stock wheels are 7.4kg each. Minilite wheels are around 5.6kg each.
D-Sport alloy underbody bracing on sale: * Copen (L880K) for D SPORT D sport floor frame bar lower brace reinforcement bar *: Real Yahoo auction salling