I say go for it.....but the bigger the tank does not mean more play time.....it all depends on your compressors and if you have the compressor h/p to fill the tank. You should get 100% duty cycle compressors and I would suggest having 2 compressors installed. That way if for what ever reason one of your compressors fail, you don't get stranded with the car laid out.
I would also suggest 3/8 air line over 1/2 because 1/2 air line will drop your car quickly and may slam it on the ground to hard if your not careful.
Here's a good place to start reading about all the components of air ride and what they all do: http://www.airbagit.com/v/vspfiles/kb_html/index.html