Manchester United chief executive David Gill has admitted he could find it difficult to implement his dream of performance-related pay at Old Trafford.Gill feels more salaries at United should be 'incentive-based', as they are at many City institutions in London.But, in the highly competitive world of Premiership football, he is not convinced it can be introduced.'Personally, I would like to see players' salaries more variable, where they win rewards if we are winning,' Gill told the Financial Times.'But that is a difficult thing to do in this business. In the City, there are huge City bonuses but the actual base salaries are not huge.'We pay very well as it is. All our players are paid very well and very appropriately.'Gill, speaking after United confirmed their profits rose by £20million to £30.8million last year, confirmed the impending appointment of a chief operating officer, to oversee all revenue streams, finance, human resources, legal and property issues and IT.He also maintained he is comfortable with the debt levels incurred by the Glazer family in their controversial takeover of the club in 2005, particularly now he can anticipate a massive rise in revenue from the new Premier League TV contract, plus increased sponsorship deals with AIG, Air Asia/Tourism Malaysia, Kumho Tire, Budweiser and Audi.'This is a very well-structured debt profile and all obligations can be met,' he said.