There are hidden cars all around the city but the main one,s are if u go on the map look at the very top st pancras there is a road that goes straight down with no side streets well if u go down from st pancras turn right down a hidden side street u will find a garage to save cars in and if u follow it there are lots of hidden cars and allsorts of types of terrain to test ur driving skill. also near barbican on the map to the left it looks like a fence go down one theres a lotus cop chase car.