Simply applying the principles of ISO 9001 can be a game changer. They are, after all, a collection of best practices.
Largely based on two main themes, shipping quality products (no defects) and continual improvement, I have seen companies that have caught the vision and embraced what ISO 9001 can do for them move from not knowing their on-time delivery results (when finally first measured found to be below 40%), not knowing their level of customer satisfaction, and making a poor attempt at controlling product quality, move to having stellar results on all three of those indicators, and to their surprise, discovering that life actually got easier in the process because they gained the tools to resolve problems in a more permanent manner.
Before, they believed that to survive that they had to tell their customers whatever they wanted to hear to survive, and then worry about how and when to fill the order. They felt they had no choice. They had no idea what their lead time was, and didn't involve their engineers or buyers until they had an order. They were flying blind, not knowing their shop capacity, shop load, not knowing how to determine lead times, and not knowing ahead of time how they might make the products or what supplier lead times they may encounter. Indeed, they made only a feeble attempt to quote lead time, only accept whatever the customer requested.
It is a thing of beauty when they get their act together.