[jim76]

i went for a ZX5 and must admit it was a great choice. my results improved instantly, making regional A finals and qualifying 4th at the F3's this year.
the car is cheap compared to others. you do need to spend a small amount on key areas to make it 100% reliable or to to improve maintenance, but on the whole it is a great car. Second hand they are currently dirt cheap. You should be able to pick up a fully modified car with carbon shock towers and top deck etc for less than £150.

any of the main chassis are good cars in the right hands. it just depends on how you like your car to handle. best thing as always is go o your local club and see if you can have a few laps on different peoples cars to see which one suits you.