No
Unless you want the noise. Going to 3 inch you loose to much backpressure. You also don't want to waste that much money on crush bends. The reason exhaust cost so much is that they are usually bolt in replacements with mandrel bent tubing. They usually put the research into pipe diameters and everything, take it from someone who worked at an exhaust shop and went through exhaust like candy. If you really want to mess with it do it right the first time. As for Performance Products, great magazine for getting part numbers and names of products then doing searches on the web and getting cheaper prices. You can beat the 500 for the magnaflow if you look around, I believe someone posted on here previously that price including shipping not to long ago. Definately go with the cat back from magnaflow or borla/TRD. It is worth the extra money. Thats my .02
Trevor