SQL Server : how can I measure database performance increase after index maintenance? We are using a SQL Server 2005 database.

We currently have no maintenance on our databases indexes. Some of our indexes are showing over 85% fragmentation when looking at the table sys.dm_db_index_physical_stats.

We plan to reorganise the indexes on our own server as a test before performing the same operation on a client site. On our own server any negative impact will have minimal or no effect on our business. After this we will set up an automated plan to reorganise the indexes.

But before being able to roll this out to our client sites (2005 and 2008r2) we will have to justify the action and to do this we have to show non-technical people a measure of improvement. How can I justify my existence? How do I measure/demonstrate any improvements?
You could use the RML utilities to capture a workload trace before and after the index rebuild and compare execution times.

RML utilities come with a reporter application that can compare the workload analysis of two trace files.

You can download it from here:

X64: http://download.microsoft.com/download/0/a/4/0a41538e-2d57-40ff-ae85-ec4459f7cdaa/RMLSetup_AMD64.msi

X86: http://download.microsoft.com/download/4/6/a/46a3217e-f523-4cc6-96e9-df73dd0fdd04/RMLSetup_X86.msi

The comparison will be more meaningful if the two workloads are comparable, even better if identical.