Upper engine cleaning product from Subaru

[RSKiwi]

Ok so I have been chipping away on an NZ forum about carbon build up....(oh dear....its one of those threads)....and it has been mentioned that the likes of Subaru at every major service spray in an upper engine cleaning solution to help remove engine deposits much like the carbon we of the FSI gen see.

'Apparently' it is similar to seafoam but that is not my area of expertise so I really have no idea, but has anyone on here been spraying in a cleaner every 6k miles? Some guys in NZ seem to be using it but no one has taken the head off to check how well it has worked.

I know it wont solve the problem but if it slows down the accumulation process after a clean it may be well worth adding to the service list.

Any experience out there of using these products?