[RFI] Buying New Vehicle - RFI issues with these models?

[Al Plant N5UM]

I am getting ready to purchase a new vehicle to replace my trusty 2000 
Chrysler mini-van that now has 157K miles.

I am considering the following smaller / more efficient vehicles:

Chevrolet Cobalt
Chevrolet HHR
Pontiac Vibe

Does anyone on the reflector know of any RFI issues that would impact HF 
mobile operation in any of these, and any hints at how to correct?   I 
plan to install my IC706MK2G and mounts for my hamsticks and ATAS100 
antennas on the new car.   

Thanks and 73,

Al  N5UM