Since getting my '03 RX300 (used), I've changed my oil twice and had it changed now twice.
Apparently, the guy at Pep Boys forgot to make sure that there was no old filter gasket stuck to the engine, so the new filter didn't get a good seal. This is like one of the most basic things you should do before installing a new filter, especially if you're "professional". The location of the filter shouldn't make a difference, especially when viewed from below.
Anyhow, you can imagine the result. Oil (under engine pressure) sprayed all over the front of the engine compartment through the resulting leak. The shop floor had so much oil on the floor, it looked somebody had been stabbed to death. Any horizontal area in the engine compartment at or below filter level has a little pool of shiny new 5w30, and lots of other parts have a sheen of fresh oil. I'm not convinced they did a good enough job cleaning up their boo boo, so I'm considering lobbying for professional engine cleaning (doesn't need to be show quality) on their dime. But, I'm wondering if steam cleaning per se is even advisable on an RX300?