You can get coils for tarmac or gravel for the stock struts. The gravel coils are a fair bit stiffer than the stock SVX rates, but allow for longer travel. The tarmac. Well, it depends on the stiffness you want. A general rule of thumb in terms of track suspension: keep the suspension firm yet supple, and run big swaybars. If your springs are so stiff *like mine* that your tires loose contact with the road surface, then your loosing traction and negating the use of the suspension in and of itself.
The best coils on the market:
http://www.swiftsprings.com/products-ss_spec_r.html
Give them a call, tell them what your looking to obtain performance wise and they can get you just what you need.
