I have said before that the McLaren development prowess is largely driven by the teams performance in 2009. Prior to that, they have started with a car which was never that far off the pace, and have been nip and tuck with the other top teams.
In 2009, the only team really developing the car at any pace other than McLaren were Red Bull, and McLaren were able to beat them at the kind of circuits which require good low speed grip, plus the McLaren had KERS, the Red Bull did not.
none of the usual protagonists, Ferrari, Brawn and Renault really made any significant developments through the season, and allowed McLaren to get to the top, once they had established the reasons for their issues.
This season, the top 4 teams are all throwing the kitchen sink at the cars, hence McLaren gains (if any) are simply maintaining the gap, rather than allowing them to close it, if anything the gap is getting larger.
In short, work on understanding the car and the issues, in relation to fixing them next year. any parts which will fit both years can be brought forward for evaluation, but for goodness sake, do not sacrifice next years performance for a solitary win/podium this year, otherwise my somewhat fragile and jaded loyalty may be rent assunder.