Which exhaust is most powerful but looks close to stock

I was wondering which company made the most powerful cat back system that looked closest to stock and not like a bee can. I don't really want it to be loud, I just want the performance. I have noticed a lot of posts about Apexi and Greddy, both of those appear to be really big exhausts, I don't want to smack it while going over a speed bump. Thanks for the help.