I have changed and upgraded all shocks and springs, anti roll bar, fitted poly bushes, engine and brake upgrades. Don't be tempted to lower the car too much, mine was lowerd when I bought it and the suspension was bottoming out all the time so wasn't working. I raised it again and fitted koni adjustable shocks, together with a thicker rear anti roll bar transformed it. A good starting point is to fit a 'steering rack clamp and brace' this cures a design fault that allows movement in the steering rack fixing. It will sharpen the steering considerably. The engines are very strong and can be tuned reliably to levels beyond what you would want. Mine is currently at about 280 bhp. Initial power gains can be had quite cheaply. I am happy to chat about specifics.
