Now, the Greddy emanage etc, are used to control the fuelling, however, these are used for highly modified engines, when you require a fine degree of control over the engine to make the most of substantial modifications.
In the case of a car suffering from underfuelling problems, a simple re-map of the existing ECU should work, and failing that, a Dastek Unichip should be a cheap Piggy-Back solution - even if still overkill..