Just thought I would provide the update to the questions I asked for the reference of others:

1. As per the earlier posts, VOA is not a problem.

2. Taxi from Airport area to Merdaka Square was about 50 minutes (good job Gaucho!) departing at 8am, and about 60 - 70 minutes the other way, departing anywhere from 4:30 - 6:30.

As expected, I had little time to enjoy the city so have little advice for others, other than to avoid the side streets during lunch hour. Cars parked every which way makes traffic a nightmare!

Also as expected, the advice given here is impeccable. Now if anyone has any idea what 2 young guys should do on a Friday night in Seoul...I'm all ears!