just had a quick look on ebay for grounding kits and came across this- http://www.ebay.co.uk/itm/Nissan-D1-Performance-Turbo-Boost-Volt-Nismo-Engine-Chip-Designed-for-350Z-370Z-/251048775464?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a73ac4f28 ive never even seen one of these before. Im not about to run out and buy it but it does claim to smooth out the idle aswell. think its just a fancy looking capacitor