The -10001 and -10004 filters contain a 1 bar (14 psi) internal bypass. I think that generally, these filters will be on the engine when it comes from the factory or after a rebuild.
It's common for Toyota to use filters without a bypass valve for subsequent use, therefore the -YZZ-- filters.
Those filters from Denso are made from molding a thick fiberglass material, 2-3 mm., over a stiff plastic skeleton, then some type of material is added which make is somewhat hard.
As you've shown, the -1000- filters have more filtration area around the periphery, better elastomers, and the bypass valve...and they cost more. I don't think that there's a good reason to use the longer filter, but I think that it will be OK.
I do not think that there are any flow concerns with Toyota filters. That was just one guy's uninformed opinion.
Ken
[ January 31, 2003, 02:52 PM: Message edited by: Ken2 ]