I am trying to figure out which Ergon grips to buy - GC3, GR2, or GR3. There are lots of positive reviews of each one in various places but not much in the way of comparison. I understand that the GC3 provides the maximum number of grips but it's not clear to me how much I would actually make use of them.

Also, I have carbon bars. Do I need to use plugs in the ends to prevent cracking when installing the Ergons? Any suggestions for what plugs to use other than the pricey ones Ergon sells itself?