Despite being late with an answer I would like to answer the question
- You gain even more performance if you physically remove the files.
- Simply all of them, except
But to disable tight couple modules you need to install another module which takes care that nothing will break. Therefore I've developed: https://github.com/Zookal/magento-mock
Zookal Mock: Transparent auto-detecting of disabled core modules and extensions and providing mock objects for not breaking Magento. Nothing to configure. No class rewrites. Only one observer. Works out of the box. You can even physically remove the files!
E.g. when you disable
Mage_Newsletter your Backend -> Customer -> Customer edit will throw weird errors. Therefore use the Mock extension!
You can even uninstall old Payment modules which have entries in the
sales_flat_order_payment table and normally break your Backend -> Sales -> Order View but the Mock extension has a transparent work around for you.
One thing to consider: It does not work on command line.