The increase in gearing will be around 3%. The acceleration in each gear will be slightly less but will be offset by each gear running 3 % faster before changing up. Motor has been re-mapped so difference will hardly be noticeable.
Speedo reads about 5% high so will actually be more accurate. As I understand it, all manufactureres make their speedos read fast by about 5% anyway. Reason? As explained to me once by a cop who pulled me for exceding the speed limit (by about 10 km/hr in a heavy truck), manufactureres don't want to be sued by motorists because they got a speeding ticket when the speedo said they were OK so deliberatetly make them read high.
Check yours out with a GPS app on your phone and tell me if I am wrong.