brake caliper slides / guide pins

[Grant Lenahan]

On the floating calipers ( ate single piston), there is a rubber  
insert that encases the guide pin and forms the bushing.
It presses into the caliper and comes as part of a new guide pin set.

1. Is there much benefit to replacing this, or is it sufficient just  
to clean the bushing and the guide pin and re-lube it?
2. If I do replace it, how does one get it out, and the new one in?  
Looks like a destructive process for the old one.

thnx

Grant

ps: not on a B5. This is front of a C4