Spring rates for most decent coilover sets are different btwn B13 & B14 chassis. Weight differences (although marginal) can make a difference in ride and performance.
To be short, if you want to do it right, use the right parts. You never know how much headache you could avoid, just by saving up for a couple more months.
"So, you want to make an econobox car handle like an F1 car, accelerate like a Pro Mod, and get 60mpg? Sure, that's easy. Start a fire, and proceed to dump a garbage bag full of money onto it."