Suspension upgrade Qs for '65 coupe

[DeltaMustang65]

Yep, just checked those kits out. I can't help but notice they seem a bit more expensive than comparable kits from MP at first glance. That plus the shipping would probably put them out of my budget. I live in stockton, and MP is roughly 15 minutes away.

I see that 620 doesn't refer to spring rate, but the diameter of the spring (I've never touched suspension before). If so, how do I find out how stiff the front springs are?

Also, what of poly vs. rubber bushings? I'm guessing from what you say that 5-leafs are meant more for track or drag strip. In that case, should I go with 4.5 leafs? 4 leafs were stock, correct?

I noticed "Carrol Shell-B" mentioned a few times while I was browsing Mustang Depot. What's the deal with that? Does he have some issue similar to Ford with people using his name?