Car seat questions

UncleBen

Hi ladies -

Does anyone have suggestions as to what car seat accessories are really needed?  Do I need two shades(one for each of the side windows)?  Do I need a rear window shade?  What about the head rest for inside the car seat?  Mirrors?  Seat protectors?  And do we need all of these things for both of our cars?  Any recommendations re: brands? 

We have the seat and the bases and will install this weekend....I just am not sure what I should get to protect the baby once he's actually in the car in his seat! 

One other question - putting the baby in the middle seat is not an option in my car.  What's safer, behind the driver or behind the passenger seat?  Do they recommend one over the other?  My car is a decent sized sedan (CTS 4) so I don't think space/size is an issue.  My husband's car is also pretty large (G8 sedan). 

Thanks!