Yes, another "WTF do I need?" question.

There's two ways to look at it. 600cc injectors x 12 = 7200cc x 15% for water = 1080cc We would sometimes bump this up for pumping losses.

We usually ignore the DC because it's a relative item with the system, if the car is at 50%IDC, so is the kit.

We can check the numbers this way. A rough estimate is 150cc per 100hp. So 631hp would use 946cc. It's somewhere in that ball park.

We have a customer in South America who tried 100% water and felt he lost power using two 1.0mm jets(about 950-1000cc) It was probably too much straight water for cooling. Using 50/50 would help that quite a bit. He was going to dump straight ethanol in the tank and see what happens.

Taking a minute to look at the numbers, you probably only have 320-350cc injectors. Using 350 and 15% gets 630cc of spray. So we have a range from 630 to 946. Assuming you are going to use two jets in the system, we could supply 4 jets, two to get you up to 950, and two a couple steps lower and you could see what works out for you.

P.S. The kit comes with 3 jets so you would need to buy one more.