I just finished my first oil change (5,000 mile) and replaced the oil drain plug with a Fumoto valve (without the nipple for drain hose). The valve had good clearance and I think you could use the one with nipple. If it did contact the panel I don't think it really would matter. The panel has some backing plus the panel itself isn't rigid so I think you could use the nipple version. I used a 64MM, 14 flats oil filter cap wrench and as others have said it worked great, in fact it fit so well I left it on the oil filter and closed the panel, didn't notice it until I was picking up my tools. In John's oil change instructions he used a 65MM and I'm sure thats works just as well and comes off easier too. I didn't have any real trouble getting the 64 off, it's just snug. I used the front and back center jack points to get the Prius up and 4 jack stands. Did this for two reasons. Changing oil is easier for me with the front wheels off, plus you're half way through doing a tire rotation. I'm 71 years old, this was the first change on this vehicle, took my time, and took an hour and a half. Next one should be less than an hour with most of that time used to jack and properly secure the jack stands. Torqued everything but the Fumoto (can't get a socket on it) This is one of the easyist vehicles I have ever changed oil on. The panel is no big deal and once it is down (used a bungee cord to keep it out of the way) the drain plug and oil filter are completely in the open. Used Mobil 1 0/20 and Toyota filter. Don't forget the old drain plug gasket, mine was stuck on the pan.