Lots of ifs and buts about the series, but I can say this... That was a dirty bloody trick with the oil, reminds me of guys in real life putting oil on the road so they can drift without damaging their tyres (Needless to say, they're serving 2 years jail for criminal damage and a few other things).
I'd love to see a 5th and 6th stage, reckon they've got plenty to base it all on.