'12 Pro 600 A-arm recommendation??

Zbroz only because they are cheap (unless you can find take offs for cheaper.) I don't recommend going 36" stance, but some guys like it.

I think 2000+miles pending on where and how it was ridden, is a good time to pull the pistons.

That tunnel shure looks rough. If it were me I would run alternative impact chromoly arms, as far as the rebuild there are several rental company's that have run the 600 up to 5,000 miles on the original motor. I say do a compression check if it looks good keep on running it.

I've run both Z-Broz and Alternative Impact and both are great.

Currently running the Alternative Impact 36", set to 37" and they work great. Great quality, outstanding customer service and this kit offers hook ups for the sway bar, which I wanted.

Z-Broz, also good stuff, high quality but if you run their 36" kit, there is NO hook up for a sway bar. Their 39" front end does hook up to the sway bar and they have that pretty cool profile.

Either way, there both great pieces of hardware!

I thought the Z-bros also used the sway bar also. Is Alt. Impact the only kit that using the sway bar

I've got a 09' 600 with 3500 miles on it no engine issues ever.
Dad has a 09' 600 with 4500miles that had to be rebuilt around 3700(bought from a rental place that put the first 2700 or so miles on it, thing was an absolute turd)
Mom has a '10 600 with 2800miles or so and no issues.

Assuming they all have the same engine(and I think they do) you should be fine till 4k+ imo. It is also funny that the 2 sleds that never had issues my family and I bought from guys on snowest. The one my dad got turned into a nightmare and spent more time in the shop than on the slopes. Hopefully yours turns out better than his did. Was yours a rental before it was totaled?

EDIT: nvm from the look of the wrap definitely not a rental. Regardless might have issues sooner due to getting total'd