The shape of Honda’s trunk is quite appropriate. For it’s size NSX has quite comfortable space arrangement. You can usually get more than 154 liters by putting down back seat in NSX. Cargo space in Honda NSX is known to be 154 liters. It appeared to be such space in Honda’s cars of 1999 year for use.
To avoid troubles make sure you carry in 1999 Honda only restricted overall weight. Honda proves it to be wise decision of making cargo capacity at 154 liters. It’s better not to load more than Honda NSX can carry.