Yes, spending money!
After the RBRR it's obvious the car needs a new radiator so, bearing in mind the competition motoring in view, there's no messing about needed.
One uprated 4 core radiator (brand spanking), full hose kit with clips, 5 litres of oil and a filter = I am £290 lighter in the pocket.
Now, I could have spent alot less but this is no time for penny pinching - proper kit is what's needed on a rally car to improve reliability.
"To finish first, first you have to finish"