My 162 Pro-Lite full of fuel with it's big tank, and my friends lightweight M7 (800 big bore) 162 full of fuel weighed within 7lb of each other on the same scales on the same day. His just felt heavier and did not handle as easily as mine due to geometry and how the weight was carried.
I personally do not like running low pressures in the front shocks. Especially on the M-series. It may make the sled feel like it's rolling easier initially, but puts the front end too low to the ground once it's up on edge: makes it push through the snow, not absorb bumps well since there is not enough stroke left, and require more effort to make it change directions. Think about what it feels like to balance a full 55 gallon barrel on it's edge and move around.
On the M1000 it helped to drill the front arm mount 3/4" lower in the tunnel. Helped lift the heavy front end and feel lighter. Holes were already in the reinforcement bracket inside the tunnel. Just had to drill them through.