"Seatings: it won't help you to much and at the end you will need to pay more and you will wait more time so if you want to upgrade them don't do it, upgrade stadium."

Not true. You dont pay more, you dont wait longer. Time and money spent for seating extensions reduces time and price of the new stadium. Advantage: You earlier have some more seats to sell. (only interesting for teams that usualy have a full house...)