but there's something to be said about not having to fill your tank ever time you drive hard for a minute or two.
Like I said in normal driving, with mulitiple WOT episodes every time I drive the car, 1 Liter lasted about 400-600 mile of driving. I basically topped it off every other tank of gas. This was with a 4 gph nozzle. One key to economical use of the injection fluid is to not trigger the injection until you need it. I monitored my boost gauge for a few days and found that it was relatively rare for me to exceed 6 -10 psi when driving. By setting the boost trigger at 10 psi, it made a major reduction in fluid use. Generally speaking you should not even need any injection at boost levels below the stock max boost of 13 - 14 psi, as you should not detonate below that level on any reasonable fuel.
That is also why it is good to use at least a 2 stage setup like a 4 gph and a 6gph wired so you get a max of 10 gph. A 2 stage setup will cut your fluid demands by about 1/3 and provide a bit of safety if one of the nozzles clog.