wow....wrong info in this thread...

upgrade seats first, then upgrade stadium. Same cost, same length of time, but you get to take advantage on increased tickets sales after each seat upgrade.

Click image for larger version.  Name: stadium1.jpg  Views: 96  Size: 96.5 KB  ID: 6952Click image for larger version.  Name: stadium2.jpg  Views: 84  Size: 97.8 KB  ID: 6953Click image for larger version.  Name: stadium3.jpg  Views: 76  Size: 97.9 KB  ID: 6954Click image for larger version.  Name: stadium4.jpg  Views: 82  Size: 99.2 KB  ID: 6955

as the photos above show, each seat upgrade decreases the cost and length of time for the stadium upgrade.