Hi, I booked through dollar and got fastlane. I booked an intermediate car. I just got a coupon for up grade in the mail.My question is should I go back and just book compact which would save me about $100.00s and use coupon for up grade? How does that work? we are going to use fastlane. I have read some where that sometimes you get there and you will go to use coupon and there will not be an upgrade available. Could some one tell me how fastlane would work using our coupon?? I have never rented a car before so this is all new to me... We are going in 5 weeks so I am trying to finish all my final ressies...thanks,,,corvair