The 4" tubing I purchased from local speed shop/fabricator. He had 2 4" elbows available, 1 small bend & 1 large bend. I picked up a 6" of straight tube & both elbow's, I returned the small elbow.
The couplers are Spectra performance part # 9771, the MAF adapter is a spectra performance 9774. Both were purchased from Amazon. The 110 degree elbow was purchased from Ebay.
The K&N air filter I purchased from the local Advance auto parts.
If I was to do it again I would get a large 4" elbow only. There was enough material cut off of it to make the straight piece out of.