It is possible to use Max/MSP to act like an effects processor with Logic. It takes a good bit of playing around, but it can be done. I was able to do this using Soundflower (and Soundflowerbed), a free inter-application audio driver available at:
http://www.cycling74.com/products/soundflower.html
What I did was:
1) set Max's audio driver to Soundflower 16 channel
2) set Logic's audio driver to Soundflower 16 channel
3) set Max to input audio on ch3-4 and output audio on ch1-2
4) set a Logic audio track to Input1-2 and Output3-4
5) use Soundflowerbed to send the Soundflower's 1-2 audio channel to Built-in (so you can hear the treated audio stream
I believe that I am hearing the signal coming from Max not Logic. I do not know if one can record this signal. Perhaps using an Aux input or Bussing the signal somewhere you can record it. Should not be too hard.
This is only one way to achieve a connection. There may well be a way to use Rewire, but I do not know how to do this.
Does anyone know how to do this with Rewire? Also, one can convert a Max patch into a Pluggo pluging, which work as AUs in Logic.
Hope this is helpful in some way,
Mitch