i personally think 8 is the best for the graffiti hands down, i like seeing it against the farm land, i think it actually makes it stand out more.
if you were able to take it again from that spot id say play with the framing just a bit, straightening it out or getting a bit more of the track into the shot... but i definitely think that spot is the best.
and of course a better time of day or just catching it at better lighting for the sake of the landscape behind it.
...but this all assumes the cars aren't going anywhere : ) Interesting shots!