Dunno if I help but I will try, and as I live in Italy the GIVI stuff is cheaper here if you need anything (UNLESS the transport costs kill it which they did recently when a mate asked me to price some Trekker panniers). I have had several XT660Xs and my current one is 2011 registered and 2010 model year I think. I have the standard Yamaha rear carrier fitted to the bike by Alf England. I have fitted the GIVI side frames to mount the Aluminium Trekker panniers and I did not need to remove the carrier.
OK???? Good luck xxxx

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(Now sold on, sob) 2011 Blue XT660X with gold wheels, was 26,500 km.
Engine mods: K&N Stage 1 filter, DNA Stage 2 filter, snorkel removed, Kev fuel mod fitted.
Plus: smoked Puig screen, Yam aluminium sump guard, Yamaha / Acerbis handguards, Givi Trekker aluminium side cases, Leo Vince X3 cans plus Kev front fork mod and Fender Xtender. Just fitted Michelin Road Pilot 3 tyres.

SOLD the XTX for a Super Ten 1200. And just bought a Raptor 700 so staying on here for some tips....