If sound is what you are after and a wee bit of performance gain a bonus, go for a titanium back box
now there not cheap, your whole budget would get you a back box, but this is all you really need.
ƒŠƒAƒ}ƒtƒ‰[@ƒtƒƒ“ƒgƒpƒCƒv@ƒZƒ“ƒ^[ƒpƒCƒv@‹‹”r‹C now there is nothing under 159 as yet but as everything is built to order im sure they could build something for you.
Just to give you an idea, here is what mine sounds like after buying a back box
YouTube - Unicorse exhaust