Springs are springs are springs, whether they are coiled, bars or leafs. They all basically react the same way and ultimatly determine the majority of the suspension behavior. However, how the car transistions through the variety of motions and the rate and reaction of those transitions is where shock absorbers make a HUGE impact and are typically underrated by most enthusiasts as a modification to pursue.I beleive a big reason why a lot of guys think coil overs are such a hot ticket are because of the $200 each shocks that come in the kit that are matched to the spring rates. Put this good a shock under the stock suspension and you will get similar results.
What I'm getting at is while air shocks may be an acceptable bridge to getting your car where you want it to be, don't ever expect them to do much more than keep your rear in the air. They are not a true performance part and they could cause you more grief in the long haul, as others have pointed out. Ultimatly, your usage will determine how your mileage varies with their use.
BTW, I like the look and think you do need more rubber now.