05 ES330@125K and 315-320 miles per fill up

I need to improve mpg and need to change spark plug and Oxygen sensors (both front banks before CAT). No engine check light or problem, but I want to replace them at same time. I got spark plug number from Sewell lexus is 90080-91180, SK20R11. But, I could not find O2 sensors part number. It will be DIY. Any advice would be appreciated?

I search and has a few, but I could not confirm part number with OEM. Here is the list which one is correct. NGK o2 is way over price, I think.

NGK
SKU:NG24663
Price: $379.45
SKU:NG24662
Price: $416.74

Denso
SKU:NP2349042
Price: $142.13
SKU:W0133-1822046
Price: $156.95
SKU:NP2349057
Price: $156.90

NGK
IFR6T11 NGK, Laser Iridium
NGK1634124 $15

Denso
SK20R11 ND, Iridium
ND1633772, $12

Denso
Iridium IK20, Iridium Power
ND1632154, $15