Raising the read suspension

i have a pair of gabrial air shocks on the back of my duster. It gives it a nice stance. I like the raised back end look. The onlt problem i found is that when it gets cold outside the seals tend not to seal up right and they leak out all the air. right now it has the stock slant six springs. but i just bought some new rear leafs from espo.com with a 2 inch raised arch to help take some of the stress off the air shocks. I have no complaints about the ride. when the shocks are up the suspension is very stiff i think.