Ilovemountains

Hi guys, I just ordered a set of Downey 2" rear leafs and a pair of the SAW 25mm torsion bars, my truck has new Rancho RS900X shocks and a 5000 stabilizer along with 31" Revos. My stock rear springs are sagging onto the load springs and the front torsion bars have been supporting the V6 for the last 140,000 miles. I was just wondering what to expect from this upgrade and if I need to buy anything before I attempt to swap everthing out! My truck is a 1 owner 1988 extended cab V6 auto with a full K&N intake and Borla cat back. Any input would be sweet, thanks again in advance for any help, Matt