Need some help with my 85 928S

I bought a 1985 928S its a automatic, I feel the car should be quicker then it is from dead stop, What should I look at ? It runs well just I feel it should rev quicker... I do have an issue that my fan doesn't work in a/c mode but defrost it does... so I know the motor is good and I hear the ducts behind moving when I slide the position control so I think its not a vacuum issue...Freon is good because cold air does slightly come out from the ducts I just cant get the blower motor to work while in a/c. ALSO my front lip chin spoiler is not attached to the underneath of the front bumper. Looking quickly I don't see how it attaches, I am thinking maybe the mounting tabs are broken? Anyone have a diagram of how it should attach? Again I just bought this car, first one I drove .... sought of an impulse buy sight unseen.... but it checked out to be a pretty good car, other then what I just listed above and I am trying to make it as close to perfect as I can, thanks