I wouldnt call them bulletproof. I know Yamaha has had some problems with them. The rear suspension links break, the balljoints wear out quickly, they are known for shearing the teeth off of the flywheel, the starters are known for failing, they have crank bearing issues in some cases and they are known for fouling plugs frequently.
They also have issues with the rear part of the tunnel bending if you back over the snowflap. Its pretty easy to back over the snowflap when backing off of a trailer, backing down a ramp while unloading the sled from your truck or even when backing down any kind of a steep incline. The tunnel is pretty weak in that area and it doesnt take much to back over the snowflap and bend the rear part of the tunnel.
I almost bought an '07 Phazer FX 2 years ago and now Im glad I didnt buy it. Dont get me wrong, I love the Phazer but its got too many issues and there is too much potential for very expensive repairs in the long run.
When you say Wisconsin, you said it all.
'01 Polaris Indy 600 XC SP EDGE XR
Powermadd articulating bar riser with 2" riser block (total rise of 4 1/2")
red Cobra low sno-x windshield
Pure Polaris handguards with Pure Polaris mounts
almond/blue drive clutch spring with 10-60 weights
121" x 15" x .91" track with 96 studs.
Citgo Sea and Snow oil