andremike wrote:I thought an exhaust is very specificc for a car.. how do i know tge magnaflow 5x8 oval is the right choice for my car?
The piping diameter is. As far as I could gather, muffler size is subjective. Bigger muffler=quieter exhaust. Piping diameter is what gives the engine backpressure to keep low RPM torque. Pipes too big, and you have no low RPM power, but great top end. Pipes too small create scavenging in the exhaust, generating low RPM power very well, but restricting high RPM performance.
The mufflers are packed with filler, so the diameter is what determines this tradeoff. I think factory from Nissan is 2.25 from the catback, as my 2.5" midpipe looks bigger than the y-pipe it's bolted to (looks like the exhaust guy flanged the midpipe down to fit). 3" and you can start to lose low RPM power on a naturally aspirated motor.
I've heard with turbocharged cars, bigger is better, as the turbo is forcing more air, which compensates for the low RPM lack of backpressure. Members on here have done 3" without any negative side effects if i recall correctly.
I chose the 5x8's because I wanted good sound without being obnoxiously loud. These do just that, and help keep the y-pipe civil. You could also use the magnaflow 4x6, or the prefabbed kit from magnaflow, which looks like tube mufflers. Another member posted video of his, and he has the injen intake, y-pipe, and the prefabbed magnaflow kit, and mine sounds very similar, but a little deeper and a little quieter. In the end, it's subjective. Your car, your choice on how you want it to sound. Loud and heard from two blocks while being raspy, quiet, refined, only noticeable under hard acceleration, a mix, whatever. A reputable shop can definitely help point you in the right direction.
so I'm leaning towards the Stillen I just don't think it sounds as good as the Borla. Any other suggestions ? My main focus is sound right now. I considered going with one of those OBX ebay cats but I'm going to put on a y-pipe and eventually get an UpRev tune so I figured the Stillen or Borla would be a better choice. Also I know the Nismo for my car has been discontinued but I saw one for a 2.5, would it fit? The Nismo is probably my favorite out of them all honestly. Also wouldn't mind picking up a used one from someone on here if they had a Nismo for sale 
. The only thing to remember is if you do go this route be sure to explain exactly what you're looking for before they start fabricating things. The last thing you want to do is pay for something that you feel is too loud or too quiet.
) when shifting and revving and it makes my piece harder than Chinese trigonometry not gonna lie. I will forever drive with my windows down.