Looked into the cobra scene a couple of years ago. For me, by far and away the best was Gardner Douglas
. Great chassis and a one piece body tub. Andy Burrows, (proprietor) gave me a demo in his 450Bhp Chevy powered race car around Castle Coombe and it was incredible. Handling was fantastic, absolutely awesome.
Haven't plucked up the courage to do one yet but I'm sure I will one day. It will definetly be a GD and Euro version to boot as opposed to Jag based.
Give Gd a look over, I'm sure you will not be disappointed.