Im not much for estimating track times... depends on many variables... driver...climate... you get the picture... a 180* thermostat should be one of the very first mods you take into consideration... it will run you no more than 10$ and its exactly what its described as... a lower degree thermostat... I think stock is 195* but dont quote me on that... If you buy a K&N intake your jus wasting your money... I did it... It was dumb so I sold it and made my own for about 87$ its a good way to save money and you will see a better result from making your own vs. K&N... There are several write ups on how to do it and you need very little skill to get it done... As far as the headers go... the only one you can afford on a budget are the Pacesetters... never used them but im sure some one will let you know how they turned out on your car... you have enough money to build a decent car... jus do your research before you blow it on junk... If you need anything myself and the fellow members of GPF will be glad to point you in the right direction...
