J4 to the tolls is about 15 mins if you know where your going on the back roads, i can do J3 to the tolls in 10 mins on the back roads, and you come out at the tolls, i came up the M20 one day with my mate and it was Qing back past to J4, and he bet i couldn't get to Elite in Rainham essex in 30 mins, bastard took me 31 mins, but still not bad going