Has anyone used either one of these? They look pretty gimicky???? http://cgi.ebay.com/ebaymotors/Up-MPG-and-Power-for-Lexus-SC400-LS400-GS400-LX450_W0QQcmdZViewItemQQcategoryZ42604QQitemZ8054742122QQrdZ1 http://cgi.ebay.com/ebaymotors/Fuel-Ionizer-for-Lexus-SC400-LS400-GS400-LX450-MPG_W0QQcmdZViewItemQQcategoryZ42604QQitemZ8054736350QQrdZ1