Rear Shock for K6

Hi I have a 2007 1200S K6 Bandit and need to do some thing with my rear shock ( position 7 ) as when the wife and I are on it the rear shock struggles a bit. I haven't even loaded up the panniers yet.
Is it best to look at a GSXR 1000  shock (if so which one) or can you get upgraded springs for this. I have seen a lot of info here but it seems to be for the K1 to K5 1200's.
As this model sits in the middle can I drop a 1250 into it?

Thanks for any help as this K6 seems to be an orphan model.

Ive played around with different shocks, and come to the conclusion of better getting a new shock ,with a spring to suit your weight . Hagon is priced ok if your on a budget . Moose Racing nsw  sells them .

I've heard the Busa rear shock is an option for the GSX1250FA. I'm around 117kg clothed. Anyone installed one of these?

Yes they fit but you will  still have to change dog bones to get correct ride height . Then the Busa shock will be used ,maybe well used,  or even have to be serviced soon ,at about $400 for a service. The spring my not be suitable either . Its not sounding such a great idea now is it(sorry)  .Google Hagon shocks
and save your self the drama . Moose Racing is oz agent

Oh , you may have to cut the battery box also to fit the busa shock and file a bit of the linkage knuckle ,  
AND ITS A SHIT OF A JOB 

Thanks for that. I'll check it out

I BOUGHT a second had shock . Got it to fit ok the it started to leak and cost me $450 to fix it . Never again .

Took the gamble and bought a Gen 1 Busa shock, It dropped straight in with no mods needed. Clears the battery box guard with lots of room and the dog bones have room to move. The only thing is the air intake is ever so slightly covered but thats all.

The ride height is higher with the center stand still working but the tyre is just on the ground. On the plus side got new chain and sprockets as well as a carb kit from Litetex,

Now to play and learn it as it corners differently now
.
Thanks everyone that helped.