This is what you want:
Smith and Wesson Shield Stainless Steel Guide Rod Assembly - Stainless Steel Guide Rods
My 95 lb wife can rack my Shield. The stock spring is used in both the 9 mm and .40 cal so it's overkill. I've also dry-Teflon lubed every moving part on my Shield, which helped in making it easier to rack (including the RSA). Firing a hundred rounds or so also helps break things in. If you side with the purists you can always use wet lube after you've treated it with dry lube and you'll find you won't need as much wet lube not to mention the gun staying cleaner\being easier to clean.
The gun has a lifetime warranty. Keep the stock spring handy and if you have any supposed wear issues when you send it back in.
There are various videos for helping woman rack a slide but I found this one the most helpful:
How to Rack a Slide - YouTube