Hi,
Well, a trace level on the MIM Service of Verbose would definitely slow things down considerably.
Then it also depends on which rulesets (MPRs) are triggered during the Export.
Both the Service and the database are involved in the export (and a lot of Stored Procedures, Brokers, and so on).
I think you should start by changing the log level, and then looking at what rulesets are triggered.
Of course network/data could be a culprit, but that's not the place I'd start looking.
There are parameters to fine tune in the MIM Service, but you should probably rule out other things before starting to change them.
You should also check that you don't have many errors on the export. That could make the MIMMA start doing single exports instead of composite exports (which could slow down the export with a factor of say 8-25 times). Check that in the Request log in the MIM Portal.
Br,
Leo