SAP implementation timelines and cost

How has SAP implementation timelines changed over the last 5 years (for a typical project which includes all R/3...

modules for 50/250/1000 users)? Also, how would the total implementation costs vary for these scenarios?

In my experience the timelines for R/3 projects have become shorter over the past years. This may be due to the increased experience working with this tool and a sound methodology. Although a reduced timeline should lead to reduce costs this is not necessarily the case. Many factors can affect cost such as auxiliary spending for infrastructure, training and a increase rate for experienced resources.