What are some performance differences when compiling your code in these mode?
- debug
- release / distribution
are the default settings optimized for app store (distribution)? what are some ways to optimize performance even more by tweaking the settings?
You'll need to compile your app in both configurations and run some performance tests to answer that question. The advantages gained are highly dependent on what the program does.
I've done some performance testing on CPU intensive code on Mac OS X for Project Euler problems and I've found that release applications are usually about twice as fast. However, as soon as you start doing IO or graphics, the advantage drops.