Interesting read.
My old car had a S3 intercooler and no a/c core and Owen had the same set up but with the addition but with a Forge Twintercooler. Both cars well all but identical other than mine had Revo S2+ and he had GIAC Extreme. When I logged both cars on a hot Scottish day (20oC), there was 0.5-1oC difference in intake temperature across the revs.
What I am interested to know is this though - with the Forge Twintercooler fitted, with an a/c core in place, does 3 cores being in front of the radiator cause the coolant temperature to rise significantly/are there any adverse effects of having 4 cores?
Also, does the overall effect of the original S3 intecooler with the stainless end tanks, when paired with the Forge Twintercooler, work out to be more efficicent than a single THS?