by DougD » Mon May 15, 2017 3:57 am
It depends on the characteristics of the existing strap vs. the replacement strap and your individual flex and fit needs.
FWIW, my (nominally) 130 flex Lange RX's have a non-elastic strap that locks with a cam buckle. Once set, it doesn't move... at all. I discussed booster straps with Diana. As they are elastic, she advised me to try them ONLY if I wanted a softer or more progressive forward flex. I don't want that, so I didn't bother. YMMV of course.
Booster straps do have other uses. ToddW uses TWO on each boot to optimize his tongue-shin fit and reduce hot spots. As I have a similar issue, I may try a booster strap lower down without removing my existing strap.
Others will have different experiences.