To save or not to save?

So often I read what it is we need to do to save fuel, and my head tells me yes yes yes, thats the way.. but when I drive.. My heart says, agh whats this pansy driving about.. performance car, but driving like its a corolla.

So I did the calculation, and at this stage in my life, my current non fuel saving driving habits are worth the extra pennies to me.

So with good decent driving in town, I would average Around 10 - 11 litres per 100 km, with spirited driving, as I drive current, it ranges between 13 - 14l /100km.. so thats 3 litres per 100 km.

11l/100km = 550km off a 60litre tank (Best Case)
14l/100km = 425km off a 60litre tank (Worst Case)

So I get 125km more if I drive frugally, which = 12L.
12L X R13 = R150 Saving per tank.

I fill up roughly 3 tanks a month or so, so thats R450 saving total in a month.

My point, for me, R450pm is a small price to pay to have ultimate enjoyment everytime I drive my car. I did this calculation, so everytime I get in, i know exactly what its costing me to drive fast, and I don't mind. My head is at ease, and my heart is happy. Before I did this calculation, I would feel a bit guilty, but not anymore.

Now this is my personal kinda view, and I am in a financial situation which allows me to do this.

IF you do the calculation, is your saving worth the driving habit change?