I would not reuse the stock rails. Buy an premade frame. Don't buy the cheap coil overs that are a shock with springs slid over them. spend the extra money and get a four link not the ladder bars, and get the housing back braced now.
I agree With getting a real coil over. However ladder bars will work just fine on almost any application. Granted 4 link is the best for a track car. Just depends on your cash flow and how much adjustability you want.