It is a bit tight no doubt, but it is not too bad if you take your time. Just don't force anything. If you are not comfortable working in tight areas like this, I completely understand. Some things I did (that I did not mention above) may make it easier for folks.
1) I temporarily threaded an 8 inch cable tie through the wires on the OEM connector (on the right side on the on the part that pops out to the right). Once in place, that allowed me to use it as a "handle" to hold and guide the connector so it wouldn't slip down to an area that is hard to reach. Once you get the OEM connector disconnected (hardest part for me), reconnecting the JB connector wasn't too bad. When you are done with the cable tie (at some point it will get in the way), clip it off the OEM connector while being careful not to snip the wires.
2) Another thing you can do is move the hose over as well as loosen up and pop up some of the brackets that sit around the area above where you need to work. I loosened the bracket (with the star bit), but it really didn't give much more room to work. Perhaps it did help more than I realized, but it didn't seem like it!
As George stated, the car will run a bit better on map 1 after plug A is connected, Plus, you will have map 6 capability as well. I think the high end is definitely stronger on map 1 after it is able to use the algorithm using the RPM. Now that I am on map 6, I won't be going back to map 1 since I can run more boost up top while ramping up slower so I don't lose traction so often.
In addition to that it was also really easy for me to get mine once I removed the factory air box. Then I was able to access the connector with my fingers.