a lot of the weights listed on that link are bogus.
the stock Hood
is around 20 lbs NOT 50 for one huge example.
also the seats weigh about 34 lbs not 40+.
they have the right ideas but don't look at the actual weight.
also they do not account for whp only factory rated power.
my car personally is at 12:1 power to weight.
also rotating weight loss such as lighter/smaller rims play a huge role as well.