JDM DB8 (Matt?), yes I am aware that buddy club offers more than 1 type of exhaust, however when most people refer to Buddy Club exhaust, they are referring to the spec II (in my experiences).
OP: the reason I am suggesting a magnaflow muffler to just be replace the muffler that is on there is because it seems like you don't have the budget set aside for a full cat back exhaust, but still want the sound of an exhaust. You also said that you don't want to worry about cops, and just a magnaflow muffler will be significantly quieter that the canister style counterparts. The reason I had the stock muffler cut out and a magnaflow welded in was not for the performance, it was because my car (being a HI car) had a rusted OEM muffler and I was sick of listening to all the leaks. I was originally looking for just a stock axleback, but the magnaflow alternative turned out to be a cheaper route (and I gained some MPGs). now, you say you already have 2.5" piping, so you *might* notice some gains with an exhaust, but in my opinion if you are adding an exhaust for the hp on an otherwise stock car, it is pointless. If you are doing it because you like the sound of an exhaust, then great! no problem there.
here is a pic for reference of my old "exhaust" on the DA.