First, I hope I am in the correct section. I am looking at a 2014 zr7000 limited and a 2015 7000 rr. Anyone know of major differences in these? I believe zr has 137 and rr has 129. I am used to two strokes riding mostly aggressive on poorly groomed trails and ditchbanging. Not in an area where we typically have lots of snow. Been trying out a Nytro for the last year and just want to try a more balanced four stroke. Thanks for any help!