I developed a very noisy/squeeky front right shock. When I had an oil change last week, I asked to have looked at.
Mechanic says its a bad shock. So, do I replace just the one, or should I replace both front shocks? BTW, they did not carry shocks for Jag, but told me if I found one, they would install it. Where is best online site?

 

Probable best to do them in pairs so they stay are even side to side.

If you don't have the adaptive shocks, then even the OEM Bilsteins aren't too bad a price at about $100 each. Rockauto, parts geek, SNG Barratt, lots of places carry them for similar prices.

 

ALWAYS replace them in pairs. Otherwise steering geometry, braking and tire life will suffer to some degree.

 

While you're in there, check your upper shock mounts. I know it's a big expense, but the labor won't be that much more. They're going to fail eventually.