[Silver69Camaro]

Chad,
I know you didn't ask me but I pretty much set the wheels and tires last.

For some reason, people always want to build a car around an existing set of wheels, a back seat, and a fuel tank. None of those should matter. You should never limit yourself to a specific backspace, but obviously you need to keep it reasonable so a manufacturer can actually produce the product (this is what JP is referring to). But here's what I do:

1. Build front suspension first; have ride height, approx. tire diameter and ride height, and CG location.
2. Build rear suspension to accomodate front suspension for solid axles; if IRS is used, build front and rear suspensions together.
3. Repeat, because the first design never works the way you thought.

But first and foremost, you need to be realistic about what suspension properties you want. 99% of the people here want the appeal of a race car, but don't actually want to drive one. If it is a true street car, even with some moderate autocross or lapping, don't get overboard with caster and camber gain; and choosing a suspension frequency "race car" high will make it terrible to drive on real roads. Be realistic.