Should I use the Pre & the Post Workout supplements along with the whey protein or that would be too much?

I've been gradually gaining a lot of physical strength & increasing my testosterone level over the years of my workouts by just using the whey protein by itself. I almost can bench press twice of my body weight. So I don't know if the Pre & the Post workouts would make any difference in my overall performance? I know the Pre & the Post workout supplements have small dose of creatine in them and I've never used creatine before because there are a lot of information about the creatine in term of its possibility of giving the consumers the negative side effects such as damaging the kidneys & livers.