If I were to have a set of lowering springs that were 6" in length and were 300/lb springs, would I have an identical ride to springs that were 8" in length and were also 300/lbs?

Also, what is a good rate (lbs) for the front and back of an ITR as a street car? Something that won't cause me to bounce all over the place, and that isn't too stiff but more of a factory type ride?

 

Yes, if it is a linear spring. Not enough info if it is a progressive type spring.