What is the difference between 4 cylinder springs Convertible/Coupe?

are you talking about the front springs compared to the font springs of a v8? if so, they are a lot softer. better weight transfer but you need softer struts too, or adjustable ones. i run strange 10 way struts with 4 banger springs.

why order them you can get them from pick your part or a junkyard cheap
 
I have to run softer struts as well eh? i didnt realize that....well murrays has them for $40 and i figure why the hell not most people want $20 for used old ones so might as well cough up the extra $20 for new ones