I will be starting the Beach Body Insanity work out soon, but I was wondering....?

If I do an additional 20 minutes of Pilates every other day, do you think it'll help give me less bulky muscles? You see, I have some muscle definition already, and I know the Insanity work out is supposed to get you ripped in 60 days, but I don't want to be scary muscular, considering i'd like to have more of a slender yet defined muscles. So, I was hoping that incorporating Pilates would help to lengthen my muscles some, so that they wouldn't turn out to be so bulky? Or would it hinder me to do that additional workout? And I know I may get suggestions to do a different type of work out instead of Insanity if I don't want to bulk up, but I want to get in shape faster and that work out offers that to me. Thanks for your responses!