First kind: Blue, Forward Voltage (V) : 3.0-3.2, Forward Current (mA):<= 30
Second kind: Purple, DC FORWARD VOLTAGE:3.7V TYPICAL, DC FORWARD CURRENT:20mA
If you mix the two kinds, you will be limited to running 20mA per string. If you run them on separate strings, you can run 30mA through the blue ones, and 20mA through the Purple ones. I would recommend the latter.
Three blues in series: 3x3.1V = 9.3V. When the car is running, the supply voltage is 14.2V, so put a resistor in series with each string of three. Resistor is Er/Ir = (14.2-9.3)/0.03 = 163Ω, round to standard value of 162Ω. Power dissipation in resistor is E^2/R = 0.15W so a 1/4W resistor is fine.
Three purples in series: 3x3.7V = 11.1V. When the car is running, the supply voltage is 14.2V, so put a resistor in series with each string of three. Resistor is Er/Ir = (14.2-11.1)/0.02 = 155Ω, round to standard value of 156Ω. Power dissipation in resistor is E^2/R = 0.06W so a 1/4W resistor is fine.