Ok- After 98K, I'm starting to feel the "early" affects of needing to replace the shocks on the rear. Most of my driving has been highway milage... I have already seen the rears will be about each and the front, around 0 each. My question-can I replace the rear without having to do a four wheel alignment? Also-are "air shocks" available for the PT, if so where? Thanks in advance and safe driving to all this holiday weekend-