How big exactly? Going past 2.5" might result in power/torque losses down low. Which results in lack of "oomph" from takeoff.
A cat-back system will mostly give just sound. Take a look into getting some extractors as well
A cheap favourite is a Redback system. I don't remember what extractors go with this setup (might be Genie/Redback?) but I remember this being noted as a good bang-for-your-buck mod.
Judging by your username though, you want a turbo. If that's the case, don't buy an exhaust system yet, save your pennies for the turbo setup and buy an exhaust system to match
Turbo exhausts and NA exhausts don't match