I think charge coolers are good for cars that spend a lot of time in "town" traffic - ie: often stop/starting, lower speeds, more using the lower three gears than the upper 2....

Increased capacity I/C's are better tho if you do a lot of out of town driving and cain it a lot

IE: if my S1 had been my commuter car I'd have probably fitted a charge cooler, as it is smaller (not blocking the rad) and for the reasons above, but if it was a weekend/fun only car (like it was) and I spent most of the time in it whizzing about country roads and duel carriage ways in higher gears and higher speeds then deffo a larger I/C

Sadly it had neither and I sold it