Bigbore pistons and springs on multiple Kyosho cars

[martgifford]

Hi,
I have just got back into tinkering with my cars - 3 running big bores and 1 running small bores. I have plenty of piston options and spring sets for the small bores but for the big bores i am limited to just the standard spring sets

ZX6 I have kit springs (Gold/Gold with 2 hole pistons)
RB5SP2WC I have kit springs and kit pistons (i need to check what these are, but assume they are also Gold)
ZX5FS2SP I have springs that I got when I bought a new set of big bore dampers with 5 hole pistons - again I assume they are Gold

Can I assume that when I have been buying these Kyosho cars that the Gold spring is the standard in the Kyohso kits and also if you buy the shocks as a part they will be Gold too.

I just looked at the price of a pair of Kyosho pistons and they are quiet expensive. Does anyone know if there are cheaper after market sets with plenty of different piston sizes. And for general astro turf use - if I have 3 cars running big bores, i heard gold is good for the rear, what colours are a good purchase for the front.

Any advice on good starting standards would be great.

Thanks very much