You usually won't find 3" or 3.5" intake piping or couplers in places like Pep Boys and Autozone. I think the 3.7l intake is 3.5" inner diameter tube. Just measure the outer diameter of the throttle body, and that's the size inner diameter tube you can use. Rubber fittings/couplers will stretch a little...
Ebay, has the correct direct bolt-on systems, where you can simply change the filters they sell, to K&N. If you buy locally, the parts to build one? It will cost a LOT more, over 100.00, and that's $60+ for just the K&N filter cone... I will be buying one from Ebay pretty soon, just need to wait for the tax money. I have three to four intake cone filters lying around that I will use... The Ebay ones also come with brackets to hold the intake in place, so you won't need to fashion your own, like I did with the Avenger I had...
