The eyelet extensions have enabled me to get more forward flex in my ankle while still maintaining lateral stability, previously the only way I could get sufficient forward flex and knee bend was to lace the top of the skate loosly or skip the top eyelet, both of these options resulted in not enough stability. Check out http://www.55flex.com/innovation.html if you havent already and I think there is a thread on here somewhere about the eyelet extensions also. As for the 3mm heel lift, It didn't feel as different as I was expecting, I was able to adjust quite quickly, the skates now feel nicer on forward crossovers and it has improved my skating slightly in this area, if you feel like your weight is on your heels a bit too much at times I'd reccomend the heel lifts, otherwise they probably aren't necessary.