I originally had my sidecar on an 07 GS. I live on a hill, and pretty much all of Vermont is hilly. Honestly, I never had a problem with the gearing. The only reason I changed to the GSA was the sidecar did horrible things to my range, and the larger gas tank restored a decent range. The enduro tranny didn't make a difference I could notice, but when I converted to a car tire that plus the tranny made uphill starts a tiny bit easier in stop and go traffic. But this is Vermont. We have Rush Minute, not Rush Hour. Stop and go here lasts about two minutes.
I got a sidecar to travel with my dog. He never complains, is delighted to be with me, approves of my dietary choices, is a social butterfly who helps me meet folks, appreciates a good beer, snuggles better than my wife, and hangs on my every word as if it's the most profound thing he's ever heard. TravelsWithBarley.com