Front track shock laid down, limiter in the highest setting, shock settings soft all around. You want the suspension as a whole to pull up into the tunnel, tightening the limiter and laying the shock down alow the front to pull up into the chassis rather than plow through the snow.
Best option is to turn the shocks to their softest setting, like he said and let the limiter strap out.
A lot of guys have relocated the front mounting hole to where the RMK has theirs, might be a small divet in the tunnel to mark this, but I have heard great results after doing this.
Biggest difference would be a new track, if you visit with tracks USA they sometimes buy the track back from you when you order throught them, sucks getting a new track right away but this will be the most effective option.
Tighten the limiter for snowmobility, reduced trenching and increased control. Loosen the limiter for increased transfer. The Polaris design over transfers, ESP with the bent rail models.
The new chassis gets on top of the snow MUCH better than the previous IQ model where the shock laydown and short limiters were needed.
I have found that the new sled is balanced right out of the box with the limiter straps at the stock setting of all the way out, when I messed with mine I ended up getting to much ski pressure and really went backwards with the setup. I put it back to stock and it got on top of the snow better again.
I think a lot more fine tuning can be done with the shock setup, and the assault shocks are already going to come to you with a VERY stiff setting on them, the softest settings on them are going to get you closer to the RMK shocks, although still a little stiffer.