Agree with illyan, robins car has been turned down because running it on the old settings, he damaged a turbo, so it was lowered to give a better operating tolerance.
An intercooler cannot give Higher horsepower joe, a larger intercooler just allows better heat dispersion as the engine and turbo will run hotter because it receiving more fuel/air mix, so all it does is help the engine temperature to run at its correct running temperature with any other adverse effect ie cracking turbo's etc as an example(in robins case).It has no affect on improving horsepower.If you add a full exhaust joe, then yes your car will produce towards your figure that youve been given.Golfgirls car produced 260bhp as stock on a set of rollers , then went on a dyno dynamics and got stock bhp 227bhp.
Its just the accuracy of the rollers that give these differences and nether robins or chris's cars are not sick!.
Like ive said before, we need everyone on a SAME set of rollers to proove this once and for all.