I have a 2000 XJ8 Vanden Plas. It has 120K on it. I've kept it up and have owned it for 10 years. Do the shocks need to be replaced? I have no idea how to know for sure, but "want" to replace them just because they have never been replaced. If I do, will the ride be "better" that what I have now? I plan to replace them with Original Equip....cost quoted 1100.....installed. Is that a good price? Thank you so much.