where is the oil filter located at? I tried to change the oil the other day and I found the oil pan. I removed all of the underbody panels but couldn't find the oil filter anywhere

It's still in the same old hideous location as the previous RX300 generation. Looking from the top down, you'll see a silver metalic heat cover covering the front exhaust manifold, reach just beneath the manifold into the engine, and you'll feel/see the filter. DO NOT do this while engine is hot.

Good luck.