I have worked with about 19 integrations that our company has taken on in the past 2 years. Speed has been largely dictated by the size of the acquisition and the nature (tech only, new product, integrated product, etc). What I have found is that the most important aspect of speed of integration is reaching the Minimally Viable Integration state. Both companies have to reach the point where they can do business as a new, integrated unit and be successful. Reaching the MVI state must be achieved and then there can be a pause while things just move forward. It is the move from MVI to Fully Integrated State that I am finding to have vastly different timeframes in our company. We have some integrations that have been in MVI for over 2 years, awaiting actions that will bring them into FIS. Others operate in MVI for just a few months before being brought into FIS. It is other factors, especially culture and the integration of culture, that go a long way toward determine how long this move from MVI to FIS will take. Decide upon a speed that allows for each step in integration to take place before moving along to the next. That should be the determining factor to have a successful integration.