The biggest problem the Icon has is the cuff itself. The boot struggles with flex. IMO the cuff is poorly designed. The thick liner is bad for racing.
You can change the flex of the boot (there is a two position flex adjuster on the spine) and it will make a noticeable difference. There are also flex cuts on the lower and putting the two pieces in will stiffen flex. You can make the flex stiffer if you bolt the cuff to the shell which is hard (i think impossible) with the stock cuff.
This is why i suggest replacing the stock cuff with the XT-17's race cuff. It is the best thing you can do. The lower of the Icon is good (heel is narrow (only the heel); the ankle area is a medium volume fit (although it could have been narrower but it has room for the ankle to flex freely and are not blocked by a too narrow shell); the mid foot is a medium foot; the instep is medium and the forefoot is accomodating but hoolds the foot properly.
The poorly designed cuff is a bad idea for this shell which is good for a lot of people (except those with narrow feet). The Endoframe is the heart of the shell and transmits energy to the ski. The other material used is softer.
My shell is a 26. The cuff is a 25. This is important. The cuff fits perfectly on the shell. All i had to do is fix it to the shell where the Dual Pivot lower holse are with the screws from the XT's cuff. But i think the screw from the Dual Pivot would work,too (although i did not try).
Now i have a zero preload boot (where the lower strap rests on the instep) which is more responsive. The stock cuff did not rub on the lower if i remember correctly.
The fit is perfect. It flexes as well as the XT. A smooth flex (no sound).
I bolted the cuff to the shell to make the boot more responsive. Previously, i cut the lower shell to make it a hinged design more responsive to foot steering and i could bolt it in one place unfortunately. But it is enough b/c the bolt allows the boot to return to neutral after flexing it. The difference is visible.
Maybe you can get a pair of used XT's and use the cuffs. Remember, the cuff has to be one size smaller than the shell to work perfectly.
If you have any questions feel free to ask or send a PM.
The cuff hold my skinny lower leg extremely well and the footbones can articulate in the shell. With the lower leg hold, the heel is cemented into the heel pocket. I have enough room at the ankle bones to flex freely. The rear half of the foot is very tight fitting while the forefoot is comfortable (the big toe has room to articulate).
Regarding the stance, i am more upright in the boot now.
Oh, i almost forgot. I threw away the stock liner and am using the Diablo Race R leather lace up liner (the copy of the Nordica leather lace up liner). Simply the best liner i ever had. From now on the Nordica liner is the only one i am going to get. Much better than the Lange RL11 liner or Atomic RT liner. I can't even close the cuff if the stock liner is in the boot