Keep in mind he has an SR20...that's quite an enginecaveman said:Do you mind if I ask you why you went from ford to nissan? Cause I'm looking to go from a spec v to a mustang.
The larger the displacement, the deaper the sound. A exhaust on a 2.5l nissan is not going to sound like a honda with a fart can on it. Just keep a cat in place and don't run a streight through muffler and you should be fine. I would keep a resenator too. I don't know if the cat backs that are sold come with that or not. NA engines and open exhaust is not a good thing.
And if you are going Mustang, wait on the SVT Cobra! 465 HP, independent rear suspension pulling over 1G on the skidpad and about 30 grand price wise. (Not to mention it looks as sick as any car I have ever seen!)
AEM is a good name, HotShot is too. Cheaper CAIs have poor mounting designs as well as lesser build quality and if they wobble, they can blow an MAF rather easily. Place Racing supposedly makes good CAIs and a steal of a deal is going on in our Group Buy section by a company that is going out of business.
As far as best sounding exhaust, Stromung is best IMO and in the opinion of most other people. It is quiet at low RPMs and deep as all hell throughout the entire powerband. VRS is nice too and a good bit less price wise. If you keep your stock header and downpipe, a res is not as much of a necessity, but it will make your car deeper sounding. You can order a Stromung with and without them. Another great thing about their exhaust is that they are dual tipped instead of one massive tip. If you go with an aftermarket header and especially an aftermarket header and downpipe without any cats, you are going to need a huge res and muffler and it will still sound rather 'ricey'. A high flow cat will infact affect the sound for the better and it only kills about 1-2 WHP (well this is on the QR but I doubt the figure is much different from my engine to yours).