JStang pretty much named them all. If you are looking to improve your street speed then the first mod I would do is to put drag radial tires on your rear wheels. That will be the best mod you can do as far as most improvement for the least amount of money. You can take 3 to 5 tenths of a sec of your 1/4 mile with that alone. Also, make sure you get wider rear tires. I am pretty sure you will be able to fit nitto 275/40's on your rear wheels. The guys at discount tire will know for sure. I dont remember if your rear rims are 8'' or 9'' rims but if they are 9'' rims you can actually fit 315/30's on them as long as you go with Nitto because Nittos drag radials are not as wide as other companies 315 tires. I would absolutely recomend nitto though, I have a 2004 cobra
that puts out 535rwhp and 555rwtq and I have nitto drag radials. I have experimented with all the drag radials from all the different companies and Nittos drag radials are by far and away the best for everyday driving. They last almost as long as normal tires do as long as you are not beating on them every day and they give you phenominal stick. The other companies drag radials only last about 5,000 miles where the nittos give you 12,000 to 15,000. The next mod you need to do is cat back exhaust with 3.5'' tips. This will give you more hp and gas mileage. Chose the 3.5'' instead of the 2.5''. I made the mistake of chosing the 2.5'' at first and when I heard another cobra with the 3.5'' his car sounded so much better then mine I was pissed. So then I had to spend more money just to do what I should of in the first place. Next, you want to get cold air intake. Then after that you should get a SCT tuner with a custom tune. At that point there is not a whole lot you can do for speed that is still cheap, you can do under drive pulleys but thats about it. I would not change your gears if I were you, the ones you have a good for everyday driving. If you were only going to use your car at the track then you could go with 373's or 410's but not for every day driving. Unless you want to invest in a supercharger or turbo charger then I would start to work on your brakes and suspension. The suspension mods will also give you a little more speed. Stay away from nitrous
, first of all I dont like anything that only gives you power when you press a button and is not available all the time. Second, most people that get nitrous end up damaging there engines or shorten the life of there engines. Its just not worth it. When you are ready for a supercharger or turbo charger, ask again and I will help you out. Later.