I never built up the standard shocks, but ive been told they are pretty good for plastic shocks, as long as you check the shock shafts do not bind in the bottom of the shock body.
But if you can afford new shocks it is probably the way to go.
Personally i would replace the decks first, if you are on a budget go for the 3 racing decks.
It has the added advantage of drastically reducing the weight of the car. However, if you upgrade the decks i would suggest ditching stick packs if you use them.