Confused about YSS upgrades for interceptor

Hi there, I drive an interceptor and the only thing that is not working for me is suspension, more so on the roads now where I have relocated. I got to know about YSS upgrades but those are too expensive for me, are they really worth it? Is there a way I can test them before putting in my money? What changes can I expect after installing?

And how do the cheaper alternatives like way2speed compare?