It depends.
On race skis, I can absolutely appreciate the difference between my TI 130s and my Hawx XTDs, and it's not just the dramatic difference in stiffness--the TI transmits energy much more quickly and powerfully in all directions. It also keeps me more honest--if I don't have my weight in the right place both laterally and fore/aft, I don't get the response I want from the skis.
On all-mountain skis with Shifts, the performance loss isn't as dramatic (IMO), although I'll admit I haven't tried a proper A/B test recently.
The downside of that better energy transfer is that my knees and back hurt a lot more quickly in the race boots because the energy transfer back up from the snow is better, too. A teenager shouldn't have the same knee/back concerns, but depending on training level and future goals, the relative forgiveness of a downhill-oriented hybrid boot may be appreciated.