LN2>DryIce/Cascade>Single Stage/chillwater>water/Air
Depending on where you live, water might be your best solution. 10% Antifreeze in the solution and drop the rad out the window on those subzero nights
Not a big difference between SS and cold water. Dice will get you a little better, LN2 is needed for the big push. (I have not used an SS, when I bench I look for SS cooled results and aim for them
Be surprised how easy it is to beat them..
A Good SS will give you rear round performance, and properly tuned you wont get that sudden steep rise in temps when you pass the load rating
Just my 2C, some of the pros will have better more experienced answers for yah