Answers to spot the difference from previous photo:
1) One is red, the other white (dur!)
2) One has a black Portuguese number plate, the other a white Spanish one
3) The white R4 has front headrests
4) The red R4 has fancy wheels
5) The white R4 has rear mudflaps
6) The white R4 has stickers in the rear window
If you got them all, then smugly pat yourself on the back.