They look like high quality filters to me... have you tried looking at Wix/Napa Gold air filters yet? I used one in my Integra and it was top notch. I'll be going back to them exclusively after I run this Purolator that's currently on it.
Actually, the Courtesy parts price is not unreasonable! The filters are well made. I just priced a fil;ter at Pep Boys for my Frontier and it was about the same price.
I am not a big fan of the Nissan oil filter, as internally it is now constructed like a Fram. I use the NAPA golds on my engine.