McLaren Performance Updates

Does anyone know what performance updates were available from the factory in Woking when cars were in for service, things such as goodwood exhaust, remapped engine , etc, and what these updates consisted of? I have heard of higher output engines being installed as well, but not sure of the credibility of the figures given. Might be a difficult question to answer, but I'm sure someone could shed some light on it.

the only ones i know of is the hd kit and for hefty sum ( i think like 250k pounds) mclaren could make your engine "lm spec" altho i'm not sure about this