What I don't like about the Tymar filter is that it draws hot air from the engine compartment. Think of how hot it gets. I've done IAT measurements on trucks with similar intakes and they added 100 plus degrees to the IAT versus a closed filter with ducted air. Remember that an extra hundred in is an extra hundred out, plus hot air is less dense with oxy. The Tymar filter looks like a decent filter, but I've never seen any tests that prove it's efficiency. The ones I've seen look like they are a polyester filter of some type, so my presumption is they would be near a factory style filter in efficiency and I don't seriously doubt the 98 percent claims made above. The airflow increase comes from the increased filter area. Per square inch of media, it's probably about the same as a factory style filter. What it needs is an enclosure with ducted frontal air.
I could imagine a scenario where the power gains that come from an increase in airflow (which are usually small and at the upper rpm range unless the original filter is totally inadequate) are negated by hotter intake air, so whatever time and money you spent are wasted. In that scenario, the stock set is better day to day. Myself, as my testosterone levels decrease with age, I will choose filtration efficiency over airflow any time. I can remember fondly that days when I thought differently, but age has given me the opportunity to see engines that died before their time due to inadequate filtration.
As to replacing the Banks with something, I'm in the same boat. Mine is the first gen kit from '87, the "Big Box", with a square oiled cotton gauze filter and there is no alternative but to remove it, housing and all, and fab up something. Since I like the retro look, I'm sticking with it. I don't clean it often and that's a key. The dirtier they are, the better they filter and I don't clean it until the restriction gauge reaches 15 inches of water. If the option of a foam sock exists for any Banks, K&N or oil cotton gauze filter, that's the answer. That extra filtration more or less brings the filtration level the few notches it needs to be adequate, which means in the 98 to 99 percent initial area IMO. The cost in airflow isn't huge.
If you guys will permit, here are pics of my old Bum-V... built in 2000 on a diesel Blazer chassis. In the engine shot, look across tot eh far side of the engine compartment and look at that monstrous tractor air filter I installed. I eventually ducted it to outside air, though the engine compartment in that rig didn't get very hot.