Qa1????
For a street and strip car I would suggest going with the F Series. The R Series just offers a 275lbs rate (which is a little to soft for the street) I would also suggest going with a 300lbs front spring rate. But it also depends on how much you want to adjust them. For a street car singles are fine. I always recommend for a pure race car to go with the double. Below is a link to show you what all UMI Performance has to offer!
http://www.umiperformance.com/catalo...tlcf7usjev5d46
http://www.umiperformance.com/catalo...tlcf7usjev5d46
If you have any other questions feel free to ask and I will be more than glad to help!
Thanks
Brad






