Sometime have me show you the 100yd group from mine... for a factory rifle shooting factory ammo, it's just about disgusting ;)
I took it along this year when Mikey and I went down to ISSC; we stopped by in Enterprise OR on the way back and did our bit to try and save a farmer's newly planted alfalfa field from an Al Queda cell of ground squirrels
The crows and hawks were *very* happy with us!
About the American vs. Varmint version thing... when I bought mine, it looked suspiciously like a Varmint version (I've had several American models, in .22 LR and .22 WMR) but the store owner was adamant that that was the .17 HMR American version and they didn't make a Varmint version of the .17 yet. That particular store sells enough of them that I'd think they'd know, but in the end I didn't really care. It carries nicely, it shoots...
The only upgrades I've done to mine are a Brookie trigger shim/spring kit to take up some of the slop and reduce the trigger pull to about 6-8 oz., and some new stock bolts (allen head instead of those old-school slotted screws). Neither absolutely necessary, but they do make the gun that much nicer.