I would strongly consider Koni yellows with a set of Ground Control sleeves. It might not be a true coil over, but the Koni yellows are one of the best shocks and struts on the market. They have great valving for autocross and track events.

I have been told to stay away from Teins. I don't anything about the Megan racing coil overs, and a quick look at thier web site didn't offer much help.

Are you building the car to run in a particular class?