If I may add my tuppence. I don't have an intercooler but always wanted one. Now, I have had a few 80s and driven even more. I was looking at ICs because I found the performance disappointing. Yes yes, it's a 3 tonne, 20 year old monster with the CD of a semi detached property. But 4.2 6 cyl? Come on.
Well, now I have a 24v and a 12v that go like a bomb. I can't believe how quick the green 12v is. I am not aware of any twiddling with the pump at all and it still does over 20mpg on a run with winch bumper etc etc. I wouldn't dream of sticking a £700 cooler on. Not on these. There is only so fast I can drive it and the torque is mind bending already.
Given that I now know just how well one of these things can go, I have to ask if there is something that needs doing to any 80 that people think needs a cooler. See what I mean? Maybe it's a question of pump tuning to get it to do what it should?