Yet another which race series thread!

[MAVROS]

I know it's been done to death but I'm having real problems making a decision on which series to join. I was all set for the BMW Nankang compact cup, low entry fees, large grids and very few mods allowed. I looked at a car today and realised there's a fair amount of development that goes on just to be competitive. One example is the front runners are running new tyres every race! It's put me off a bit but it seems you can join a well supported series with a few professional drivers who will still find a way to spend money or an up and coming series where it's more relaxed while everyone finds their feet. I won my last race but I was in a class of four cars!
Can anyone recommend a championship which is well supported but full of genuine club racers and not pseudo race teams?
The last thread on this subject had someone suggest single seaters which piqued my interest. Can anyone recommend a value for money single seater series? Preferably with some figures to boot.
My budget is £10.000 pa for five or six double headers not including extraordinary costs, engine rebuilds, damage etc.
Cheers guys.