My EK9 (with 15 litres of 98RON fuel) weighs in at 865kgs.
Bear in mind that is fully cut to bits with fuel cell, false floor made from aluminium, plastic windows, and no wiring save what is needed. The car has a full multi-point roll cage so some weight has gone back in too. There are still some more gains to be made with carbon doors and rear hatch but money is getting tight. I could have bought two EK9s with what it cost to get it down to that weight!
865kg coupled with around 200hp B16b equals fast, and once corner weighted and setup will keep up with K powered cars no problem (on a track on slicks though, but everyone is on slicks!).
Has made me think again about re-powering with K series, as the car is plenty quick enough already, and there are minimum weights in place for the higher classes.
Any questions feel free to ask.