qwak

I,ve just returned from my maiden voyage in my '87 911 cab. It's the first time I've really had a chance to drive it after I bot it because of this long winter. Since I'm new to these cars, I was pleasantly surprised at how sweet it handles and accelerates.
I'm hoping some of you oldtimers will give me some advice on the following observations.....are they querks to porsche, or just mine, and shoul they be fixed?
Do these cars ride like buckboards...I don't mind a firm ride, but if theres a seam in the pavement it bangs and pounds up through the car...sounds like a dwarfs under there with a sledgehammer. Also, should I be concerned if my cars speedo is 10+mph off when over 50mph? Finally, with the top up, I have trouble getting the window on the drivers side to fit under the top unless I lower it and then raise it after closing the door. Other than a squeeling fan blower motor and steering wheel shimmy at 70mph it's perfect.
Thanks for any advice!