hmm well from what ive read here, napa gold ..has the oil adapter where the thread is. some here dont seem too like that. i dont remember off hand, the beta ratios of um...efficeincy@ microns.
i wouold imagine the TG is better at micron capturing particles, better effieicency. My napa , a few yars ago, i bought a silver air filter,and a silver filter..both made in poland. id di not ike the material used in the air filter, the driveworks at advance atuo was WAY better feeling material, so was the dealers it was slightly thicker and napa air filter, the air seal, came of rather easily...
thiers trade offs, at least for me. I have cut open Tg;s (for a 95 neon, and a 98 corolla after 1,500 miles ofusage). tg's have partcile board or cardboard endcaps. glued very well. screen ontop the by pass as well. no oil thread adapter thingy where it screws onto the adapeter under car. the tg has much better efficiency than the gold.